Run prettier

Gulpfile.js

@@ -21,32 +21,41 @@ function swapSrcWithLib(srcPath) {
 
 gulp.task("default", ["build"]);
 
-gulp.task("build", function () {
+gulp.task("build", function() {
-  return gulp.src(scripts, { base: base })
+  return gulp
-    .pipe(plumber({
+    .src(scripts, { base: base })
-      errorHandler: function (err) {
+    .pipe(
+      plumber({
+        errorHandler: function(err) {
           gutil.log(err.stack);
         },
-    }))
+      })
-    .pipe(newer({
+    )
+    .pipe(
+      newer({
         dest: base,
         map: swapSrcWithLib,
-    }))
+      })
-    .pipe(through.obj(function (file, enc, callback) {
+    )
+    .pipe(
+      through.obj(function(file, enc, callback) {
         gutil.log("Compiling", "'" + chalk.cyan(file.relative) + "'...");
         callback(null, file);
-    }))
+      })
+    )
     .pipe(babel())
-    .pipe(through.obj(function (file, enc, callback) {
+    .pipe(
+      through.obj(function(file, enc, callback) {
         // Passing 'file.relative' because newer() above uses a relative path and this keeps it consistent.
         file.path = path.resolve(file.base, swapSrcWithLib(file.relative));
         callback(null, file);
-    }))
+      })
+    )
     .pipe(gulp.dest(base));
 });
 
-gulp.task("watch", ["build"], function () {
+gulp.task("watch", ["build"], function() {
-  watch(scripts, { debounceDelay: 200 }, function () {
+  watch(scripts, { debounceDelay: 200 }, function() {
     gulp.start("build");
   });
 });

packages/babel-cli/src/_babel-node.js

@@ -24,9 +24,21 @@ function collect(value, previousValue): Array<string> {
 /* eslint-disable max-len */
 program.option("-e, --eval [script]", "Evaluate script");
 program.option("-p, --print [code]", "Evaluate script and print result");
-program.option("-o, --only [globs]", "A comma-separated list of glob patterns to compile", collect);
+program.option(
-program.option("-i, --ignore [globs]", "A comma-separated list of glob patterns to skip compiling", collect);
+  "-o, --only [globs]",
-program.option("-x, --extensions [extensions]", "List of extensions to hook into [.es6,.js,.es,.jsx,.mjs]", collect);
+  "A comma-separated list of glob patterns to compile",
+  collect,
+);
+program.option(
+  "-i, --ignore [globs]",
+  "A comma-separated list of glob patterns to skip compiling",
+  collect,
+);
+program.option(
+  "-x, --extensions [extensions]",
+  "List of extensions to hook into [.es6,.js,.es,.jsx,.mjs]",
+  collect,
+);
 program.option("-w, --plugins [string]", "", collect);
 program.option("-b, --presets [string]", "", collect);
 /* eslint-enable max-len */
@@ -55,23 +67,28 @@ const replPlugin = ({ types: t }) => ({
 
     VariableDeclaration(path) {
       if (path.node.kind !== "var") {
-        throw path.buildCodeFrameError("Only `var` variables are supported in the REPL");
+        throw path.buildCodeFrameError(
+          "Only `var` variables are supported in the REPL",
+        );
       }
     },
 
     Program(path) {
-      if (path.get("body").some((child) => child.isExpressionStatement())) return;
+      if (path.get("body").some(child => child.isExpressionStatement())) return;
 
       // If the executed code doesn't evaluate to a value,
       // prevent implicit strict mode from printing 'use strict'.
-      path.pushContainer("body", t.expressionStatement(t.identifier("undefined")));
+      path.pushContainer(
+        "body",
+        t.expressionStatement(t.identifier("undefined")),
+      );
     },
   },
 });
 
 //
 
-const _eval = function (code, filename) {
+const _eval = function(code, filename) {
   code = code.trim();
   if (!code) return undefined;
 
@@ -113,7 +130,7 @@ if (program.eval || program.print) {
 
     let i = 0;
     let ignoreNext = false;
-    args.some(function (arg, i2) {
+    args.some(function(arg, i2) {
       if (ignoreNext) {
         ignoreNext = false;
         return;
@@ -133,7 +150,9 @@ if (program.eval || program.print) {
 
     // make the filename absolute
     const filename = args[0];
-    if (!path.isAbsolute(filename)) args[0] = path.join(process.cwd(), filename);
+    if (!path.isAbsolute(filename)) {
+      args[0] = path.join(process.cwd(), filename);
+    }
 
     // add back on node and concat the sliced args
     process.argv = ["node"].concat(args);

packages/babel-cli/src/babel-external-helpers.js

@@ -10,8 +10,16 @@ function collect(value, previousValue): Array<string> {
   return previousValue ? previousValue.concat(values) : values;
 }
 
-commander.option("-l, --whitelist [whitelist]", "Whitelist of helpers to ONLY include", collect);
+commander.option(
-commander.option("-t, --output-type [type]", "Type of output (global|umd|var)", "global");
+  "-l, --whitelist [whitelist]",
+  "Whitelist of helpers to ONLY include",
+  collect,
+);
+commander.option(
+  "-t, --output-type [type]",
+  "Type of output (global|umd|var)",
+  "global",
+);
 
 commander.usage("[options]");
 commander.parse(process.argv);

packages/babel-cli/src/babel-node.js

@@ -33,7 +33,7 @@ function getNormalizedV8Flag(arg) {
   return arg;
 }
 
-getV8Flags(function (err, v8Flags) {
+getV8Flags(function(err, v8Flags) {
   babelArgs.forEach(function(arg) {
     const flag = arg.split("=")[0];
 
@@ -59,7 +59,10 @@ getV8Flags(function (err, v8Flags) {
         break;
 
       default:
-        if (v8Flags.indexOf(getNormalizedV8Flag(flag)) >= 0 || arg.indexOf("--trace") === 0) {
+        if (
+          v8Flags.indexOf(getNormalizedV8Flag(flag)) >= 0 ||
+          arg.indexOf("--trace") === 0
+        ) {
           args.unshift(arg);
         } else {
           args.push(arg);
@@ -80,9 +83,11 @@ getV8Flags(function (err, v8Flags) {
     if (err.code !== "MODULE_NOT_FOUND") throw err;
 
     const child_process = require("child_process");
-    const proc = child_process.spawn(process.argv[0], args, { stdio: "inherit" });
+    const proc = child_process.spawn(process.argv[0], args, {
-    proc.on("exit", function (code, signal) {
+      stdio: "inherit",
-      process.on("exit", function () {
+    });
+    proc.on("exit", function(code, signal) {
+      process.on("exit", function() {
         if (signal) {
           process.kill(process.pid, signal);
         } else {

packages/babel-cli/src/babel/dir.js

@@ -6,19 +6,27 @@ import fs from "fs";
 
 import * as util from "./util";
 
-export default function (commander, filenames, opts) {
+export default function(commander, filenames, opts) {
   function write(src, relative) {
-    if (!util.isCompilableExtension(relative, commander.extensions)) return false;
+    if (!util.isCompilableExtension(relative, commander.extensions)) {
+      return false;
+    }
 
     // remove extension and then append back on .js
     relative = relative.replace(/\.(\w*?)$/, "") + ".js";
 
     const dest = path.join(commander.outDir, relative);
 
-    const data = util.compile(src, defaults({
+    const data = util.compile(
+      src,
+      defaults(
+        {
           sourceFileName: slash(path.relative(dest + "/..", src)),
           sourceMapTarget: path.basename(relative),
-    }, opts));
+        },
+        opts,
+      ),
+    );
 
     if (!data) return false;
 
@@ -55,7 +63,7 @@ export default function (commander, filenames, opts) {
     if (stat.isDirectory(filename)) {
       const dirname = filename;
 
-      util.readdir(dirname).forEach(function (filename) {
+      util.readdir(dirname).forEach(function(filename) {
         const src = path.join(dirname, filename);
         handleFile(src, filename);
       });
@@ -71,7 +79,7 @@ export default function (commander, filenames, opts) {
   if (commander.watch) {
     const chokidar = util.requireChokidar();
 
-    filenames.forEach(function (dirname) {
+    filenames.forEach(function(dirname) {
       const watcher = chokidar.watch(dirname, {
         persistent: true,
         ignoreInitial: true,
@@ -81,8 +89,8 @@ export default function (commander, filenames, opts) {
         },
       });
 
-      ["add", "change"].forEach(function (type) {
+      ["add", "change"].forEach(function(type) {
-        watcher.on(type, function (filename) {
+        watcher.on(type, function(filename) {
           const relative = path.relative(dirname, filename) || filename;
           try {
             handleFile(filename, relative);

packages/babel-cli/src/babel/file.js

@@ -7,14 +7,14 @@ import fs from "fs";
 
 import * as util from "./util";
 
-export default function (commander, filenames, opts) {
+export default function(commander, filenames, opts) {
   if (commander.sourceMaps === "inline") {
     opts.sourceMaps = true;
   }
 
   let results = [];
 
-  const buildResult = function () {
+  const buildResult = function() {
     const map = new sourceMap.SourceMapGenerator({
       file: path.basename(commander.outFile || "") || "stdout",
       sourceRoot: opts.sourceRoot,
@@ -23,14 +23,14 @@ export default function (commander, filenames, opts) {
     let code = "";
     let offset = 0;
 
-    results.forEach(function (result) {
+    results.forEach(function(result) {
       code += result.code + "\n";
 
       if (result.map) {
         const consumer = new sourceMap.SourceMapConsumer(result.map);
         const sources = new Set();
 
-        consumer.eachMapping(function (mapping) {
+        consumer.eachMapping(function(mapping) {
           if (mapping.source != null) sources.add(mapping.source);
 
           map.addMapping({
@@ -39,14 +39,17 @@ export default function (commander, filenames, opts) {
               column: mapping.generatedColumn,
             },
             source: mapping.source,
-            original: mapping.source == null ? null : {
+            original:
+              mapping.source == null
+                ? null
+                : {
                     line: mapping.originalLine,
                     column: mapping.originalColumn,
                   },
           });
         });
 
-        sources.forEach((source) => {
+        sources.forEach(source => {
           const content = consumer.sourceContentFor(source, true);
           if (content !== null) {
             map.setSourceContent(source, content);
@@ -59,7 +62,10 @@ export default function (commander, filenames, opts) {
 
     // add the inline sourcemap comment if we've either explicitly asked for inline source
     // maps, or we've requested them without any output file
-    if (commander.sourceMaps === "inline" || (!commander.outFile && commander.sourceMaps)) {
+    if (
+      commander.sourceMaps === "inline" ||
+      (!commander.outFile && commander.sourceMaps)
+    ) {
       code += "\n" + convertSourceMap.fromObject(map).toComment();
     }
 
@@ -69,7 +75,7 @@ export default function (commander, filenames, opts) {
     };
   };
 
-  const output = function () {
+  const output = function() {
     const result = buildResult();
 
     if (commander.outFile) {
@@ -86,36 +92,45 @@ export default function (commander, filenames, opts) {
     }
   };
 
-  const stdin = function () {
+  const stdin = function() {
     let code = "";
 
     process.stdin.setEncoding("utf8");
 
-    process.stdin.on("readable", function () {
+    process.stdin.on("readable", function() {
       const chunk = process.stdin.read();
       if (chunk !== null) code += chunk;
     });
 
-    process.stdin.on("end", function () {
+    process.stdin.on("end", function() {
-      results.push(util.transform(commander.filename, code, defaults({
+      results.push(
+        util.transform(
+          commander.filename,
+          code,
+          defaults(
+            {
               sourceFileName: "stdin",
-      }, opts)));
+            },
+            opts,
+          ),
+        ),
+      );
       output();
     });
   };
 
-  const walk = function () {
+  const walk = function() {
     const _filenames = [];
     results = [];
 
-    filenames.forEach(function (filename) {
+    filenames.forEach(function(filename) {
       if (!fs.existsSync(filename)) return;
 
       const stat = fs.statSync(filename);
       if (stat.isDirectory()) {
         const dirname = filename;
 
-        util.readdirFilter(filename).forEach(function (filename) {
+        util.readdirFilter(filename).forEach(function(filename) {
           _filenames.push(path.join(dirname, filename));
         });
       } else {
@@ -123,16 +138,25 @@ export default function (commander, filenames, opts) {
       }
     });
 
-    _filenames.forEach(function (filename) {
+    _filenames.forEach(function(filename) {
       let sourceFilename = filename;
       if (commander.outFile) {
-        sourceFilename = path.relative(path.dirname(commander.outFile), sourceFilename);
+        sourceFilename = path.relative(
+          path.dirname(commander.outFile),
+          sourceFilename,
+        );
       }
       sourceFilename = slash(sourceFilename);
 
-      const data = util.compile(filename, defaults({
+      const data = util.compile(
+        filename,
+        defaults(
+          {
             sourceFileName: sourceFilename,
-      }, opts));
+          },
+          opts,
+        ),
+      );
 
       if (!data) return;
 
@@ -142,23 +166,26 @@ export default function (commander, filenames, opts) {
     output();
   };
 
-  const files = function () {
+  const files = function() {
-
     if (!commander.skipInitialBuild) {
       walk();
     }
 
     if (commander.watch) {
       const chokidar = util.requireChokidar();
-      chokidar.watch(filenames, {
+      chokidar
+        .watch(filenames, {
           persistent: true,
           ignoreInitial: true,
           awaitWriteFinish: {
             stabilityThreshold: 50,
             pollInterval: 10,
           },
-      }).on("all", function (type, filename) {
+        })
-        if (!util.isCompilableExtension(filename, commander.extensions)) return;
+        .on("all", function(type, filename) {
+          if (!util.isCompilableExtension(filename, commander.extensions)) {
+            return;
+          }
 
           if (type === "add" || type === "change") {
             util.log(type + " " + filename);

packages/babel-cli/src/babel/index.js

@@ -34,45 +34,117 @@ function collect(value, previousValue): Array<string> {
 
 /* eslint-disable max-len */
 // Standard Babel input configs.
-commander.option("-f, --filename [filename]", "filename to use when reading from stdin - this will be used in source-maps, errors etc");
+commander.option(
-commander.option("--presets [list]", "comma-separated list of preset names", collect);
+  "-f, --filename [filename]",
-commander.option("--plugins [list]", "comma-separated list of plugin names", collect);
+  "filename to use when reading from stdin - this will be used in source-maps, errors etc",
+);
+commander.option(
+  "--presets [list]",
+  "comma-separated list of preset names",
+  collect,
+);
+commander.option(
+  "--plugins [list]",
+  "comma-separated list of plugin names",
+  collect,
+);
 
 // Basic file input configuration.
 commander.option("--source-type [script|module]", "");
-commander.option("--no-babelrc", "Whether or not to look up .babelrc and .babelignore files");
+commander.option(
-commander.option("--ignore [list]", "list of glob paths to **not** compile", collect);
+  "--no-babelrc",
-commander.option("--only [list]", "list of glob paths to **only** compile", collect);
+  "Whether or not to look up .babelrc and .babelignore files",
+);
+commander.option(
+  "--ignore [list]",
+  "list of glob paths to **not** compile",
+  collect,
+);
+commander.option(
+  "--only [list]",
+  "list of glob paths to **only** compile",
+  collect,
+);
 
 // Misc babel config.
-commander.option("--no-highlight-code", "enable/disable ANSI syntax highlighting of code frames (on by default)");
+commander.option(
+  "--no-highlight-code",
+  "enable/disable ANSI syntax highlighting of code frames (on by default)",
+);
 
 // General output formatting.
-commander.option("--no-comments", "write comments to generated output (true by default)");
+commander.option(
-commander.option("--retain-lines", "retain line numbers - will result in really ugly code");
+  "--no-comments",
-commander.option("--compact [true|false|auto]", "do not include superfluous whitespace characters and line terminators", booleanify);
+  "write comments to generated output (true by default)",
+);
+commander.option(
+  "--retain-lines",
+  "retain line numbers - will result in really ugly code",
+);
+commander.option(
+  "--compact [true|false|auto]",
+  "do not include superfluous whitespace characters and line terminators",
+  booleanify,
+);
 commander.option("--minified", "save as much bytes when printing [true|false]");
-commander.option("--auxiliary-comment-before [string]", "print a comment before any injected non-user code");
+commander.option(
-commander.option("--auxiliary-comment-after [string]", "print a comment after any injected non-user code");
+  "--auxiliary-comment-before [string]",
+  "print a comment before any injected non-user code",
+);
+commander.option(
+  "--auxiliary-comment-after [string]",
+  "print a comment after any injected non-user code",
+);
 
 // General soucemap formatting.
 commander.option("-s, --source-maps [true|false|inline|both]", "", booleanify);
-commander.option("--source-map-target [string]", "set `file` on returned source map");
+commander.option(
-commander.option("--source-file-name [string]", "set `sources[0]` on returned source map");
+  "--source-map-target [string]",
-commander.option("--source-root [filename]", "the root from which all sources are relative");
+  "set `file` on returned source map",
+);
+commander.option(
+  "--source-file-name [string]",
+  "set `sources[0]` on returned source map",
+);
+commander.option(
+  "--source-root [filename]",
+  "the root from which all sources are relative",
+);
 
 // Config params for certain module output formats.
-commander.option("--module-root [filename]", "optional prefix for the AMD module formatter that will be prepend to the filename on module definitions");
+commander.option(
+  "--module-root [filename]",
+  "optional prefix for the AMD module formatter that will be prepend to the filename on module definitions",
+);
 commander.option("-M, --module-ids", "insert an explicit id for modules");
-commander.option("--module-id [string]", "specify a custom name for module ids");
+commander.option(
+  "--module-id [string]",
+  "specify a custom name for module ids",
+);
 
 // "babel" command specific arguments that are not passed to babel-core.
-commander.option("-x, --extensions [extensions]", "List of extensions to compile when a directory has been input [.es6,.js,.es,.jsx,.mjs]", collect);
+commander.option(
+  "-x, --extensions [extensions]",
+  "List of extensions to compile when a directory has been input [.es6,.js,.es,.jsx,.mjs]",
+  collect,
+);
 commander.option("-w, --watch", "Recompile files on changes");
-commander.option("--skip-initial-build", "Do not compile files before watching");
+commander.option(
-commander.option("-o, --out-file [out]", "Compile all input files into a single file");
+  "--skip-initial-build",
-commander.option("-d, --out-dir [out]", "Compile an input directory of modules into an output directory");
+  "Do not compile files before watching",
-commander.option("-D, --copy-files", "When compiling a directory copy over non-compilable files");
+);
+commander.option(
+  "-o, --out-file [out]",
+  "Compile all input files into a single file",
+);
+commander.option(
+  "-d, --out-dir [out]",
+  "Compile an input directory of modules into an output directory",
+);
+commander.option(
+  "-D, --copy-files",
+  "When compiling a directory copy over non-compilable files",
+);
 commander.option("-q, --quiet", "Don't log anything");
 /* eslint-enable max-len */
 
@@ -84,7 +156,7 @@ commander.parse(process.argv);
 
 const errors = [];
 
-let filenames = commander.args.reduce(function (globbed, input) {
+let filenames = commander.args.reduce(function(globbed, input) {
   let files = glob.sync(input);
   if (!files.length) files = [input];
   return globbed.concat(files);
@@ -92,7 +164,7 @@ let filenames = commander.args.reduce(function (globbed, input) {
 
 filenames = uniq(filenames);
 
-filenames.forEach(function (filename) {
+filenames.forEach(function(filename) {
   if (!fs.existsSync(filename)) {
     errors.push(filename + " doesn't exist");
   }

packages/babel-cli/src/babel/util.js

@@ -10,7 +10,7 @@ export function chmod(src, dest) {
 }
 
 export function readdirFilter(filename) {
-  return readdir(filename).filter(function (filename) {
+  return readdir(filename).filter(function(filename) {
     return isCompilableExtension(filename);
   });
 }
@@ -20,7 +20,10 @@ export { readdir };
 /**
  * Test if a filename ends with a compilable extension.
  */
-export function isCompilableExtension(filename: string, altExts?: Array<string>): boolean {
+export function isCompilableExtension(
+  filename: string,
+  altExts?: Array<string>,
+): boolean {
   const exts = altExts || babel.DEFAULT_EXTENSIONS;
   const ext = path.extname(filename);
   return includes(exts, ext);
@@ -63,7 +66,7 @@ function toErrorStack(err) {
   }
 }
 
-process.on("uncaughtException", function (err) {
+process.on("uncaughtException", function(err) {
   console.error(toErrorStack(err));
   process.exit(1);
 });
@@ -74,7 +77,7 @@ export function requireChokidar() {
   } catch (err) {
     console.error(
       "The optional dependency chokidar failed to install and is required for " +
-      "--watch. Chokidar is likely not supported on your platform."
+        "--watch. Chokidar is likely not supported on your platform.",
     );
     throw err;
   }

packages/babel-cli/test/index.js

@@ -27,34 +27,39 @@ const pluginLocs = [
   path.join(__dirname, "/../../babel-plugin-transform-es2015-modules-commonjs"),
 ].join(",");
 
-const readDir = function (loc, filter) {
+const readDir = function(loc, filter) {
   const files = {};
   if (fs.existsSync(loc)) {
-    readdir(loc, filter).forEach(function (filename) {
+    readdir(loc, filter).forEach(function(filename) {
       files[filename] = helper.readFile(path.join(loc, filename));
     });
   }
   return files;
 };
 
-const saveInFiles = function (files) {
+const saveInFiles = function(files) {
   // Place an empty .babelrc in each test so tests won't unexpectedly get to repo-level config.
   outputFileSync(".babelrc", "{}");
 
-  Object.keys(files).forEach(function (filename) {
+  Object.keys(files).forEach(function(filename) {
     const content = files[filename];
     outputFileSync(filename, content);
   });
 };
 
-const assertTest = function (stdout, stderr, opts) {
+const assertTest = function(stdout, stderr, opts) {
   const expectStderr = opts.stderr.trim();
   stderr = stderr.trim();
 
   if (opts.stderr) {
     if (opts.stderrContains) {
-      assert.ok(includes(stderr, expectStderr), "stderr " + JSON.stringify(stderr) +
+      assert.ok(
-        " didn't contain " + JSON.stringify(expectStderr));
+        includes(stderr, expectStderr),
+        "stderr " +
+          JSON.stringify(stderr) +
+          " didn't contain " +
+          JSON.stringify(expectStderr),
+      );
     } else {
       chai.expect(stderr).to.equal(expectStderr, "stderr didn't match");
     }
@@ -68,8 +73,13 @@ const assertTest = function (stdout, stderr, opts) {
 
   if (opts.stdout) {
     if (opts.stdoutContains) {
-      assert.ok(includes(stdout, expectStdout), "stdout " + JSON.stringify(stdout) +
+      assert.ok(
-        " didn't contain " + JSON.stringify(expectStdout));
+        includes(stdout, expectStdout),
+        "stdout " +
+          JSON.stringify(stdout) +
+          " didn't contain " +
+          JSON.stringify(expectStdout),
+      );
     } else {
       chai.expect(stdout).to.equal(expectStdout, "stdout didn't match");
     }
@@ -80,30 +90,34 @@ const assertTest = function (stdout, stderr, opts) {
   if (opts.outFiles) {
     const actualFiles = readDir(path.join(tmpLoc));
 
-    Object.keys(actualFiles).forEach(function (filename) {
+    Object.keys(actualFiles).forEach(function(filename) {
       if (!opts.inFiles.hasOwnProperty(filename)) {
         const expect = opts.outFiles[filename];
         const actual = actualFiles[filename];
 
-        chai.expect(expect, "Output is missing: " + filename).to.not.be.undefined;
+        chai.expect(expect, "Output is missing: " + filename).to.not.be
+          .undefined;
 
         if (expect) {
-          chai.expect(actual).to.equal(expect, "Compiled output does not match: " + filename);
+          chai
+            .expect(actual)
+            .to.equal(expect, "Compiled output does not match: " + filename);
         }
       }
     });
 
     Object.keys(opts.outFiles).forEach(function(filename) {
-      chai.expect(actualFiles, "Extraneous file in output: " + filename)
+      chai
+        .expect(actualFiles, "Extraneous file in output: " + filename)
         .to.contain.key(filename);
     });
   }
 };
 
-const buildTest = function (binName, testName, opts) {
+const buildTest = function(binName, testName, opts) {
   const binLoc = path.join(__dirname, "../lib", binName);
 
-  return function (callback) {
+  return function(callback) {
     clear();
     saveInFiles(opts.inFiles);
 
@@ -124,15 +138,15 @@ const buildTest = function (binName, testName, opts) {
     let stderr = "";
     let stdout = "";
 
-    spawn.stderr.on("data", function (chunk) {
+    spawn.stderr.on("data", function(chunk) {
       stderr += chunk;
     });
 
-    spawn.stdout.on("data", function (chunk) {
+    spawn.stdout.on("data", function(chunk) {
       stdout += chunk;
     });
 
-    spawn.on("close", function () {
+    spawn.on("close", function() {
       let err;
 
       try {
@@ -142,7 +156,8 @@ const buildTest = function (binName, testName, opts) {
       }
 
       if (err) {
-        err.message = args.map((arg) => `"${ arg }"`).join(" ") + ": " + err.message;
+        err.message =
+          args.map(arg => `"${arg}"`).join(" ") + ": " + err.message;
       }
 
       callback(err);
@@ -155,19 +170,19 @@ const buildTest = function (binName, testName, opts) {
   };
 };
 
-const clear = function () {
+const clear = function() {
   process.chdir(__dirname);
   if (fs.existsSync(tmpLoc)) rimraf.sync(tmpLoc);
   fs.mkdirSync(tmpLoc);
   process.chdir(tmpLoc);
 };
 
-fs.readdirSync(fixtureLoc).forEach(function (binName) {
+fs.readdirSync(fixtureLoc).forEach(function(binName) {
   if (binName[0] === ".") return;
 
   const suiteLoc = path.join(fixtureLoc, binName);
-  describe("bin/" + binName, function () {
+  describe("bin/" + binName, function() {
-    fs.readdirSync(suiteLoc).forEach(function (testName) {
+    fs.readdirSync(suiteLoc).forEach(function(testName) {
       if (testName[0] === ".") return;
 
       const testLoc = path.join(suiteLoc, testName);
@@ -179,7 +194,7 @@ fs.readdirSync(fixtureLoc).forEach(function (binName) {
       const optionsLoc = path.join(testLoc, "options.json");
       if (fs.existsSync(optionsLoc)) merge(opts, require(optionsLoc));
 
-      ["stdout", "stdin", "stderr"].forEach(function (key) {
+      ["stdout", "stdin", "stderr"].forEach(function(key) {
         const loc = path.join(testLoc, key + ".txt");
         if (fs.existsSync(loc)) {
           opts[key] = helper.readFile(loc);

packages/babel-code-frame/src/index.js

@@ -90,11 +90,11 @@ function getTokenType(match) {
  */
 
 function highlight(defs: Object, text: string) {
-  return text.replace(jsTokens, function (...args) {
+  return text.replace(jsTokens, function(...args) {
     const type = getTokenType(args);
     const colorize = defs[type];
     if (colorize) {
-      return args[0].split(NEWLINE).map((str) => colorize(str)).join("\n");
+      return args[0].split(NEWLINE).map(str => colorize(str)).join("\n");
     } else {
       return args[0];
     }
@@ -106,9 +106,15 @@ function highlight(defs: Object, text: string) {
  */
 
 function getMarkerLines(
-  loc: NodeLocation, source: Array<string>, opts: Object
+  loc: NodeLocation,
+  source: Array<string>,
+  opts: Object,
 ): { start: number, end: number, markerLines: Object } {
-  const startLoc: Location = Object.assign({}, { column: 0, line: -1 }, loc.start);
+  const startLoc: Location = Object.assign(
+    {},
+    { column: 0, line: -1 },
+    loc.start,
+  );
   const endLoc: Location = Object.assign({}, startLoc, loc.end);
   const linesAbove = opts.linesAbove || 2;
   const linesBelow = opts.linesBelow || 3;
@@ -165,12 +171,13 @@ function getMarkerLines(
   return { start, end, markerLines };
 }
 
-export function codeFrameColumns (
+export function codeFrameColumns(
   rawLines: string,
   loc: NodeLocation,
   opts: Object = {},
 ): string {
-  const highlighted = (opts.highlightCode && Chalk.supportsColor) || opts.forceColor;
+  const highlighted =
+    (opts.highlightCode && Chalk.supportsColor) || opts.forceColor;
   let chalk = Chalk;
   if (opts.forceColor) {
     chalk = new Chalk.constructor({ enabled: true });
@@ -186,7 +193,9 @@ export function codeFrameColumns (
 
   const numberMaxWidth = String(end).length;
 
-  const frame = lines.slice(start, end).map((line, index) => {
+  const frame = lines
+    .slice(start, end)
+    .map((line, index) => {
       const number = start + 1 + index;
       const paddedNumber = ` ${number}`.slice(-numberMaxWidth);
       const gutter = ` ${paddedNumber} | `;
@@ -194,7 +203,9 @@ export function codeFrameColumns (
       if (hasMarker) {
         let markerLine = "";
         if (Array.isArray(hasMarker)) {
-        const markerSpacing = line.slice(0, Math.max(hasMarker[0] - 1, 0)).replace(/[^\t]/g, " ");
+          const markerSpacing = line
+            .slice(0, Math.max(hasMarker[0] - 1, 0))
+            .replace(/[^\t]/g, " ");
           const numberOfMarkers = hasMarker[1] || 1;
 
           markerLine = [
@@ -213,7 +224,8 @@ export function codeFrameColumns (
       } else {
         return ` ${maybeHighlight(defs.gutter, gutter)}${line}`;
       }
-  }).join("\n");
+    })
+    .join("\n");
 
   if (highlighted) {
     return chalk.reset(frame);
@@ -226,7 +238,7 @@ export function codeFrameColumns (
  * Create a code frame, adding line numbers, code highlighting, and pointing to a given position.
  */
 
-export default function (
+export default function(
   rawLines: string,
   lineNumber: number,
   colNumber: ?number,
@@ -236,7 +248,7 @@ export default function (
     deprecationWarningShown = true;
 
     const deprecationError = new Error(
-      "Passing lineNumber and colNumber is deprecated to babel-code-frame. Please use `codeFrameColumns`."
+      "Passing lineNumber and colNumber is deprecated to babel-code-frame. Please use `codeFrameColumns`.",
     );
     deprecationError.name = "DeprecationWarning";
 
@@ -249,7 +261,9 @@ export default function (
 
   colNumber = Math.max(colNumber, 0);
 
-  const location: NodeLocation = { start: { column: colNumber, line: lineNumber } };
+  const location: NodeLocation = {
+    start: { column: colNumber, line: lineNumber },
+  };
 
   return codeFrameColumns(rawLines, location, opts);
 }

packages/babel-code-frame/test/index.js

@@ -2,35 +2,29 @@ import assert from "assert";
 import chalk from "chalk";
 import codeFrame, { codeFrameColumns } from "..";
 
-describe("babel-code-frame", function () {
+describe("babel-code-frame", function() {
-  it("basic usage", function () {
+  it("basic usage", function() {
-    const rawLines = [
+    const rawLines = ["class Foo {", "  constructor()", "};"].join("\n");
-      "class Foo {",
+    assert.equal(
-      "  constructor()",
+      codeFrame(rawLines, 2, 16),
-      "};",
+      [
-    ].join("\n");
-    assert.equal(codeFrame(rawLines, 2, 16), [
         "  1 | class Foo {",
         "> 2 |   constructor()",
         "    |                ^",
         "  3 | };",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
-  it("optional column number", function () {
+  it("optional column number", function() {
-    const rawLines = [
+    const rawLines = ["class Foo {", "  constructor()", "};"].join("\n");
-      "class Foo {",
+    assert.equal(
-      "  constructor()",
+      codeFrame(rawLines, 2, null),
-      "};",
+      ["  1 | class Foo {", "> 2 |   constructor()", "  3 | };"].join("\n"),
-    ].join("\n");
+    );
-    assert.equal(codeFrame(rawLines, 2, null), [
-      "  1 | class Foo {",
-      "> 2 |   constructor()",
-      "  3 | };",
-    ].join("\n"));
   });
 
-  it("maximum context lines and padding", function () {
+  it("maximum context lines and padding", function() {
     const rawLines = [
       "/**",
       " * Sums two numbers.",
@@ -44,7 +38,9 @@ describe("babel-code-frame", function () {
       "  return a + b",
       "}",
     ].join("\n");
-    assert.equal(codeFrame(rawLines, 7, 2), [
+    assert.equal(
+      codeFrame(rawLines, 7, 2),
+      [
         "   5 |  * @param b Number",
         "   6 |  * @returns Number",
         ">  7 |  */",
@@ -52,10 +48,11 @@ describe("babel-code-frame", function () {
         "   8 | ",
         "   9 | function sum(a, b) {",
         "  10 |   return a + b",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
-  it("no unnecessary padding due to one-off errors", function () {
+  it("no unnecessary padding due to one-off errors", function() {
     const rawLines = [
       "/**",
       " * Sums two numbers.",
@@ -69,7 +66,9 @@ describe("babel-code-frame", function () {
       "  return a + b",
       "}",
     ].join("\n");
-    assert.equal(codeFrame(rawLines, 6, 2), [
+    assert.equal(
+      codeFrame(rawLines, 6, 2),
+      [
         "  4 |  * @param a Number",
         "  5 |  * @param b Number",
         "> 6 |  * @returns Number",
@@ -77,35 +76,39 @@ describe("babel-code-frame", function () {
         "  7 |  */",
         "  8 | ",
         "  9 | function sum(a, b) {",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
-  it("tabs", function () {
+  it("tabs", function() {
     const rawLines = [
       "\tclass Foo {",
       "\t  \t\t    constructor\t(\t)",
       "\t};",
     ].join("\n");
-    assert.equal(codeFrame(rawLines, 2, 25), [
+    assert.equal(
+      codeFrame(rawLines, 2, 25),
+      [
         "  1 | \tclass Foo {",
         "> 2 | \t  \t\t    constructor\t(\t)",
         "    | \t  \t\t               \t \t ^",
         "  3 | \t};",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
-  it("opts.highlightCode", function () {
+  it("opts.highlightCode", function() {
     const rawLines = "console.log('babel')";
     const result = codeFrame(rawLines, 1, 9, { highlightCode: true });
     const stripped = chalk.stripColor(result);
     assert.ok(result.length > stripped.length);
-    assert.equal(stripped, [
+    assert.equal(
-      "> 1 | console.log('babel')",
+      stripped,
-      "    |         ^",
+      ["> 1 | console.log('babel')", "    |         ^"].join("\n"),
-    ].join("\n"));
+    );
   });
 
-  it("opts.linesAbove", function () {
+  it("opts.linesAbove", function() {
     const rawLines = [
       "/**",
       " * Sums two numbers.",
@@ -119,17 +122,20 @@ describe("babel-code-frame", function () {
       "  return a + b",
       "}",
     ].join("\n");
-    assert.equal(codeFrame(rawLines, 7, 2, { linesAbove: 1 }), [
+    assert.equal(
+      codeFrame(rawLines, 7, 2, { linesAbove: 1 }),
+      [
         "   6 |  * @returns Number",
         ">  7 |  */",
         "     |  ^",
         "   8 | ",
         "   9 | function sum(a, b) {",
         "  10 |   return a + b",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
-  it("opts.linesBelow", function () {
+  it("opts.linesBelow", function() {
     const rawLines = [
       "/**",
       " * Sums two numbers.",
@@ -143,16 +149,19 @@ describe("babel-code-frame", function () {
       "  return a + b",
       "}",
     ].join("\n");
-    assert.equal(codeFrame(rawLines, 7, 2, { linesBelow: 1 }), [
+    assert.equal(
+      codeFrame(rawLines, 7, 2, { linesBelow: 1 }),
+      [
         "  5 |  * @param b Number",
         "  6 |  * @returns Number",
         "> 7 |  */",
         "    |  ^",
         "  8 | ",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
-  it("opts.linesAbove and opts.linesBelow", function () {
+  it("opts.linesAbove and opts.linesBelow", function() {
     const rawLines = [
       "/**",
       " * Sums two numbers.",
@@ -166,78 +175,82 @@ describe("babel-code-frame", function () {
       "  return a + b",
       "}",
     ].join("\n");
-    assert.equal(codeFrame(rawLines, 7, 2, { linesAbove: 1, linesBelow: 1 }), [
+    assert.equal(
-      "  6 |  * @returns Number",
+      codeFrame(rawLines, 7, 2, { linesAbove: 1, linesBelow: 1 }),
-      "> 7 |  */",
+      ["  6 |  * @returns Number", "> 7 |  */", "    |  ^", "  8 | "].join(
-      "    |  ^",
+        "\n",
-      "  8 | ",
+      ),
-    ].join("\n"));
+    );
   });
 
   it("opts.forceColor", function() {
     const marker = chalk.red.bold;
     const gutter = chalk.grey;
 
-    const rawLines = [
+    const rawLines = ["", "", "", ""].join("\n");
-      "",
+    assert.equal(
-      "",
+      codeFrame(rawLines, 3, null, {
-      "",
+        linesAbove: 1,
-      "",
+        linesBelow: 1,
-    ].join("\n");
+        forceColor: true,
-    assert.equal(codeFrame(rawLines, 3, null, { linesAbove: 1, linesBelow: 1, forceColor: true }),
+      }),
-      chalk.reset([
+      chalk.reset(
+        [
           " " + gutter(" 2 | "),
           marker(">") + gutter(" 3 | "),
           " " + gutter(" 4 | "),
-      ].join("\n"))
+        ].join("\n"),
+      ),
     );
   });
 
-  it("basic usage, new API", function () {
+  it("basic usage, new API", function() {
-    const rawLines = [
+    const rawLines = ["class Foo {", "  constructor()", "};"].join("\n");
-      "class Foo {",
+    assert.equal(
-      "  constructor()",
+      codeFrameColumns(rawLines, { start: { line: 2, column: 16 } }),
-      "};",
+      [
-    ].join("\n");
-    assert.equal(codeFrameColumns(rawLines, { start: { line: 2, column: 16 } }), [
         "  1 | class Foo {",
         "> 2 |   constructor()",
         "    |                ^",
         "  3 | };",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
   it("mark multiple columns", function() {
-    const rawLines = [
+    const rawLines = ["class Foo {", "  constructor()", "};"].join("\n");
-      "class Foo {",
-      "  constructor()",
-      "};",
-    ].join("\n");
     assert.equal(
-      codeFrameColumns(rawLines, { start: { line: 2, column: 3 }, end: { line: 2, column: 16 } }), [
+      codeFrameColumns(rawLines, {
+        start: { line: 2, column: 3 },
+        end: { line: 2, column: 16 },
+      }),
+      [
         "  1 | class Foo {",
         "> 2 |   constructor()",
         "    |   ^^^^^^^^^^^^^",
         "  3 | };",
-      ].join("\n"));
+      ].join("\n"),
+    );
   });
 
   it("mark multiple columns across lines", function() {
-    const rawLines = [
+    const rawLines = ["class Foo {", "  constructor() {", "  }", "};"].join(
-      "class Foo {",
+      "\n",
-      "  constructor() {",
+    );
-      "  }",
-      "};",
-    ].join("\n");
     assert.equal(
-      codeFrameColumns(rawLines, { start: { line: 2, column: 17 }, end: { line: 3, column: 3 } }), [
+      codeFrameColumns(rawLines, {
+        start: { line: 2, column: 17 },
+        end: { line: 3, column: 3 },
+      }),
+      [
         "  1 | class Foo {",
         "> 2 |   constructor() {",
         "    |                 ^",
         "> 3 |   }",
         "    | ^^^",
         "  4 | };",
-      ].join("\n"));
+      ].join("\n"),
+    );
   });
 
   it("mark multiple columns across multiple lines", function() {
@@ -249,7 +262,11 @@ describe("babel-code-frame", function () {
       "};",
     ].join("\n");
     assert.equal(
-      codeFrameColumns(rawLines, { start: { line: 2, column: 17 }, end: { line: 4, column: 3 } }), [
+      codeFrameColumns(rawLines, {
+        start: { line: 2, column: 17 },
+        end: { line: 4, column: 3 },
+      }),
+      [
         "  1 | class Foo {",
         "> 2 |   constructor() {",
         "    |                 ^",
@@ -258,7 +275,8 @@ describe("babel-code-frame", function () {
         "> 4 |   }",
         "    | ^^^",
         "  5 | };",
-      ].join("\n"));
+      ].join("\n"),
+    );
   });
 
   it("mark across multiple lines without columns", function() {
@@ -270,12 +288,14 @@ describe("babel-code-frame", function () {
       "};",
     ].join("\n");
     assert.equal(
-      codeFrameColumns(rawLines, { start: { line: 2 }, end: { line: 4 } }), [
+      codeFrameColumns(rawLines, { start: { line: 2 }, end: { line: 4 } }),
+      [
         "  1 | class Foo {",
         "> 2 |   constructor() {",
         "> 3 |     console.log(arguments);",
         "> 4 |   }",
         "  5 | };",
-      ].join("\n"));
+      ].join("\n"),
+    );
   });
 });

packages/babel-core/src/config/build-config-chain.js

@@ -7,14 +7,14 @@ import micromatch from "micromatch";
 import { findConfigs, loadConfig } from "./loading/files";
 
 type ConfigItem = {
-  type: "options"|"arguments",
+  type: "options" | "arguments",
   options: {},
   dirname: string,
   alias: string,
   loc: string,
 };
 
-export default function buildConfigChain(opts: {}): Array<ConfigItem>|null {
+export default function buildConfigChain(opts: {}): Array<ConfigItem> | null {
   if (typeof opts.filename !== "string" && opts.filename != null) {
     throw new Error(".filename must be a string, null, or undefined");
   }
@@ -44,9 +44,9 @@ export default function buildConfigChain(opts: {}): Array<ConfigItem>|null {
 }
 
 class ConfigChainBuilder {
-  filename: string|null;
+  filename: string | null;
   configs: Array<ConfigItem>;
-  possibleDirs: null|Array<string>;
+  possibleDirs: null | Array<string>;
 
   constructor(filename) {
     this.configs = [];
@@ -57,16 +57,14 @@ class ConfigChainBuilder {
   /**
    * Tests if a filename should be ignored based on "ignore" and "only" options.
    */
-  shouldIgnore(
+  shouldIgnore(ignore: mixed, only: mixed, dirname: string): boolean {
-    ignore: mixed,
-    only: mixed,
-    dirname: string,
-  ): boolean {
     if (!this.filename) return false;
 
     if (ignore) {
       if (!Array.isArray(ignore)) {
-        throw new Error(`.ignore should be an array, ${JSON.stringify(ignore)} given`);
+        throw new Error(
+          `.ignore should be an array, ${JSON.stringify(ignore)} given`,
+        );
       }
 
       if (this.matchesPatterns(ignore, dirname)) return true;
@@ -74,7 +72,9 @@ class ConfigChainBuilder {
 
     if (only) {
       if (!Array.isArray(only)) {
-        throw new Error(`.only should be an array, ${JSON.stringify(only)} given`);
+        throw new Error(
+          `.only should be an array, ${JSON.stringify(only)} given`,
+        );
       }
 
       if (!this.matchesPatterns(only, dirname)) return true;
@@ -89,21 +89,27 @@ class ConfigChainBuilder {
    */
   matchesPatterns(patterns: Array<mixed>, dirname: string) {
     const filename = this.filename;
-    if (!filename) throw new Error("Assertion failure: .filename should always exist here");
+    if (!filename) {
+      throw new Error("Assertion failure: .filename should always exist here");
+    }
 
     const res = [];
     const strings = [];
     const fns = [];
 
-    patterns.forEach((pattern) => {
+    patterns.forEach(pattern => {
       if (typeof pattern === "string") strings.push(pattern);
       else if (typeof pattern === "function") fns.push(pattern);
       else if (pattern instanceof RegExp) res.push(pattern);
-      else throw new Error("Patterns must be a string, function, or regular expression");
+      else {
+        throw new Error(
+          "Patterns must be a string, function, or regular expression",
+        );
+      }
     });
 
-    if (res.some((re) => re.test(filename))) return true;
+    if (res.some(re => re.test(filename))) return true;
-    if (fns.some((fn) => fn(filename))) return true;
+    if (fns.some(fn => fn(filename))) return true;
 
     if (strings.length > 0) {
       let possibleDirs = this.possibleDirs;
@@ -123,7 +129,7 @@ class ConfigChainBuilder {
         }
       }
 
-      const absolutePatterns = strings.map((pattern) => {
+      const absolutePatterns = strings.map(pattern => {
         // Preserve the "!" prefix so that micromatch can use it for negation.
         const negate = pattern[0] === "!";
         if (negate) pattern = pattern.slice(1);
@@ -131,7 +137,9 @@ class ConfigChainBuilder {
         return (negate ? "!" : "") + path.resolve(dirname, pattern);
       });
 
-      if (micromatch(possibleDirs, absolutePatterns, { nocase: true }).length > 0) {
+      if (
+        micromatch(possibleDirs, absolutePatterns, { nocase: true }).length > 0
+      ) {
         return true;
       }
     }
@@ -150,16 +158,16 @@ class ConfigChainBuilder {
     });
   }
 
-  mergeConfig({
+  mergeConfig({ type, options: rawOpts, alias, dirname }) {
-    type,
-    options: rawOpts,
-    alias,
-    dirname,
-  }) {
     // Bail out ASAP if this file is ignored so that we run as little logic as possible on ignored files.
-    if (this.filename && this.shouldIgnore(rawOpts.ignore || null, rawOpts.only || null, dirname)) {
+    if (
+      this.filename &&
+      this.shouldIgnore(rawOpts.ignore || null, rawOpts.only || null, dirname)
+    ) {
       // TODO(logan): This is a really cross way to bail out. Avoid this in rewrite.
-      throw Object.assign((new Error("This file has been ignored."): any), { code: "BABEL_IGNORED_FILE" });
+      throw Object.assign((new Error("This file has been ignored."): any), {
+        code: "BABEL_IGNORED_FILE",
+      });
     }
 
     const options = Object.assign({}, rawOpts);
@@ -168,13 +176,19 @@ class ConfigChainBuilder {
 
     const envKey = getEnv();
 
-    if (rawOpts.env != null && (typeof rawOpts.env !== "object" || Array.isArray(rawOpts.env))) {
+    if (
+      rawOpts.env != null &&
+      (typeof rawOpts.env !== "object" || Array.isArray(rawOpts.env))
+    ) {
       throw new Error(".env block must be an object, null, or undefined");
     }
 
     const envOpts = rawOpts.env && rawOpts.env[envKey];
 
-    if (envOpts != null && (typeof envOpts !== "object" || Array.isArray(envOpts))) {
+    if (
+      envOpts != null &&
+      (typeof envOpts !== "object" || Array.isArray(envOpts))
+    ) {
       throw new Error(".env[...] block must be an object, null, or undefined");
     }
 
@@ -196,11 +210,13 @@ class ConfigChainBuilder {
     });
 
     if (rawOpts.extends) {
-      if (typeof rawOpts.extends !== "string") throw new Error(".extends must be a string");
+      if (typeof rawOpts.extends !== "string") {
+        throw new Error(".extends must be a string");
+      }
 
       const extendsConfig = loadConfig(rawOpts.extends, dirname);
 
-      const existingConfig = this.configs.some((config) => {
+      const existingConfig = this.configs.some(config => {
         return config.alias === extendsConfig.filepath;
       });
       if (!existingConfig) {
@@ -214,4 +230,3 @@ class ConfigChainBuilder {
     }
   }
 }
-

packages/babel-core/src/config/caching.js

@@ -13,7 +13,7 @@ type CacheConfiguratorObj = {
   invalidate: <T>(handler: () => T) => T,
 };
 
-type CacheEntry<ResultT> = Array<[ ResultT, () => boolean ]>;
+type CacheEntry<ResultT> = Array<[ResultT, () => boolean]>;
 
 /**
  * Given a function with a single argument, cache its results based on its argument and how it
@@ -22,7 +22,7 @@ type CacheEntry<ResultT> = Array<[ ResultT, () => boolean ]>;
 export function makeStrongCache<ArgT, ResultT>(
   handler: (ArgT, CacheConfigurator) => ResultT,
   autoPermacache?: boolean,
-): (ArgT) => ResultT {
+): ArgT => ResultT {
   return makeCachedFunction(new Map(), handler, autoPermacache);
 }
 
@@ -34,22 +34,24 @@ export function makeStrongCache<ArgT, ResultT>(
 export function makeWeakCache<ArgT: {}, ResultT>(
   handler: (ArgT, CacheConfigurator) => ResultT,
   autoPermacache?: boolean,
-): (ArgT) => ResultT {
+): ArgT => ResultT {
   return makeCachedFunction(new WeakMap(), handler, autoPermacache);
 }
 
-type CacheMap<ArgT, ResultT> = Map<ArgT, CacheEntry<ResultT>>|WeakMap<ArgT, CacheEntry<ResultT>>;
+type CacheMap<ArgT, ResultT> =
+  | Map<ArgT, CacheEntry<ResultT>>
+  | WeakMap<ArgT, CacheEntry<ResultT>>;
 
 function makeCachedFunction<ArgT, ResultT, Cache: CacheMap<ArgT, ResultT>>(
   callCache: Cache,
   handler: (ArgT, CacheConfigurator) => ResultT,
   autoPermacache: boolean = true,
-): (ArgT) => ResultT {
+): ArgT => ResultT {
   return function cachedFunction(arg) {
-    let cachedValue: CacheEntry<ResultT>|void = callCache.get(arg);
+    let cachedValue: CacheEntry<ResultT> | void = callCache.get(arg);
 
     if (cachedValue) {
-      for (const [ value, valid ] of cachedValue) {
+      for (const [value, valid] of cachedValue) {
         if (valid()) return value;
       }
     }
@@ -64,7 +66,8 @@ function makeCachedFunction<ArgT, ResultT, Cache: CacheMap<ArgT, ResultT>>(
 
     if (!result.configured) {
       // eslint-disable-next-line max-len
-      throw new Error([
+      throw new Error(
+        [
           "Caching was left unconfigured. Babel's plugins, presets, and .babelrc.js files can be configured",
           "for various types of caching, using the first param of their handler functions:",
           "",
@@ -83,12 +86,12 @@ function makeCachedFunction<ArgT, ResultT, Cache: CacheMap<ArgT, ResultT>>(
           "",
           "  // If testing for a specific env, we recommend specifics to avoid instantiating a plugin for",
           "  // any possible NODE_ENV value that might come up during plugin execution.",
-        "  var isProd = api.cache(() => process.env.NODE_ENV === \"production\");",
+          '  var isProd = api.cache(() => process.env.NODE_ENV === "production");',
           "",
           "  // .cache(fn) will perform a linear search though instances to find the matching plugin based",
           "  // based on previous instantiated plugins. If you want to recreate the plugin and discard the",
           "  // previous instance whenever something changes, you may use:",
-        "  var isProd = api.cache.invalidate(() => process.env.NODE_ENV === \"production\");",
+          '  var isProd = api.cache.invalidate(() => process.env.NODE_ENV === "production");',
           "",
           "  // Note, we also expose the following more-verbose versions of the above examples:",
           "  api.cache.forever(); // api.cache(true)",
@@ -98,21 +101,18 @@ function makeCachedFunction<ArgT, ResultT, Cache: CacheMap<ArgT, ResultT>>(
           "  // Return the value that will be cached.",
           "  return { };",
           "};",
-      ].join("\n"));
+        ].join("\n"),
+      );
     }
 
     if (!result.never) {
       if (result.forever) {
-        cachedValue = [
+        cachedValue = [[value, () => true]];
-          [value, () => true],
-        ];
       } else if (result.invalidate) {
-        cachedValue = [
+        cachedValue = [[value, result.valid]];
-          [value, result.valid],
-        ];
       } else {
         cachedValue = cachedValue || [];
-        cachedValue.push([ value, result.valid ]);
+        cachedValue.push([value, result.valid]);
       }
       callCache.set(arg, cachedValue);
     }
@@ -121,7 +121,11 @@ function makeCachedFunction<ArgT, ResultT, Cache: CacheMap<ArgT, ResultT>>(
   };
 }
 
-function makeCacheConfig(): { cache: CacheConfigurator, result: *, deactivate: () => void } {
+function makeCacheConfig(): {
+  cache: CacheConfigurator,
+  result: *,
+  deactivate: () => void,
+} {
   const pairs = [];
 
   const result = {
@@ -137,7 +141,8 @@ function makeCacheConfig(): { cache: CacheConfigurator, result: *, deactivate: (
     active = false;
   };
 
-  const cache: CacheConfigurator = Object.assign((function cacheFn(val) {
+  const cache: CacheConfigurator = Object.assign(
+    (function cacheFn(val) {
       if (typeof val === "boolean") {
         if (val) cache.forever();
         else cache.never();
@@ -145,43 +150,71 @@ function makeCacheConfig(): { cache: CacheConfigurator, result: *, deactivate: (
       }
 
       return cache.using(val);
-  }: any), ({
+    }: any),
+    ({
       forever() {
-      if (!active) throw new Error("Cannot change caching after evaluation has completed.");
+        if (!active) {
-      if (result.never) throw new Error("Caching has already been configured with .never()");
+          throw new Error(
+            "Cannot change caching after evaluation has completed.",
+          );
+        }
+        if (result.never) {
+          throw new Error("Caching has already been configured with .never()");
+        }
         result.forever = true;
         result.configured = true;
       },
       never() {
-      if (!active) throw new Error("Cannot change caching after evaluation has completed.");
+        if (!active) {
-      if (result.forever) throw new Error("Caching has already been configured with .forever()");
+          throw new Error(
+            "Cannot change caching after evaluation has completed.",
+          );
+        }
+        if (result.forever) {
+          throw new Error(
+            "Caching has already been configured with .forever()",
+          );
+        }
         result.never = true;
         result.configured = true;
       },
       using<T>(handler: () => T): T {
-      if (!active) throw new Error("Cannot change caching after evaluation has completed.");
+        if (!active) {
+          throw new Error(
+            "Cannot change caching after evaluation has completed.",
+          );
+        }
         if (result.never || result.forever) {
-        throw new Error("Caching has already been configured with .never or .forever()");
+          throw new Error(
+            "Caching has already been configured with .never or .forever()",
+          );
         }
         result.configured = true;
 
         const key = handler();
-      pairs.push([ key, handler ]);
+        pairs.push([key, handler]);
         return key;
       },
       invalidate<T>(handler: () => T): T {
-      if (!active) throw new Error("Cannot change caching after evaluation has completed.");
+        if (!active) {
+          throw new Error(
+            "Cannot change caching after evaluation has completed.",
+          );
+        }
         if (result.never || result.forever) {
-        throw new Error("Caching has already been configured with .never or .forever()");
+          throw new Error(
+            "Caching has already been configured with .never or .forever()",
+          );
         }
         result.invalidate = true;
         result.configured = true;
 
         const key = handler();
-      pairs.push([ key, handler ]);
+        pairs.push([key, handler]);
         return key;
       },
-  }: CacheConfiguratorObj));
+    }: CacheConfiguratorObj),
+  );
 
   return { cache, result, deactivate };
 }

packages/babel-core/src/config/helpers/environment.js

@@ -1,7 +1,5 @@
 // @flow
 
 export function getEnv(defaultValue: string = "development"): string {
-  return process.env.BABEL_ENV
+  return process.env.BABEL_ENV || process.env.NODE_ENV || defaultValue;
-    || process.env.NODE_ENV
-    || defaultValue;
 }

packages/babel-core/src/config/index.js

@@ -5,13 +5,13 @@ import manageOptions from "./option-manager";
 
 export type ResolvedConfig = {
   options: Object,
-  passes: Array<Array<[ Plugin, ?{} ]>>,
+  passes: Array<Array<[Plugin, ?{}]>>,
 };
 
 /**
  * Standard API for loading Babel configuration data. Not for public consumption.
  */
-export default function loadConfig(opts: mixed): ResolvedConfig|null {
+export default function loadConfig(opts: mixed): ResolvedConfig | null {
   if (opts != null && typeof opts !== "object") {
     throw new Error("Babel options must be an object, null, or undefined");
   }

packages/babel-core/src/config/loading/files/configuration.js

@@ -41,13 +41,16 @@ export function findConfigs(dirname: string): Array<ConfigFile> {
         BABELRC_FILENAME,
         BABELRC_JS_FILENAME,
         PACKAGE_FILENAME,
-      ].reduce((previousConfig: ConfigFile|null, name) => {
+      ].reduce((previousConfig: ConfigFile | null, name) => {
         const filepath = path.join(loc, name);
         const config = readConfig(filepath);
 
         if (config && previousConfig) {
-          throw new Error(`Multiple configuration files found. Please remove one:\n- ${
+          throw new Error(
-            path.basename(previousConfig.filepath)}\n- ${name}\nfrom ${loc}`);
+            `Multiple configuration files found. Please remove one:\n- ${path.basename(
+              previousConfig.filepath,
+            )}\n- ${name}\nfrom ${loc}`,
+          );
         }
 
         return config || previousConfig;
@@ -73,7 +76,9 @@ export function loadConfig(name: string, dirname: string): ConfigFile {
   const filepath = resolve.sync(name, { basedir: dirname });
 
   const conf = readConfig(filepath);
-  if (!conf) throw new Error(`Config file ${filepath} contains no configuration data`);
+  if (!conf) {
+    throw new Error(`Config file ${filepath} contains no configuration data`);
+  }
 
   return conf;
 }
@@ -83,7 +88,9 @@ export function loadConfig(name: string, dirname: string): ConfigFile {
  * throw if there are parsing errors while loading a config.
  */
 function readConfig(filepath) {
-  return (path.extname(filepath) === ".js") ? readConfigJS(filepath) : readConfigFile(filepath);
+  return path.extname(filepath) === ".js"
+    ? readConfigJS(filepath)
+    : readConfigFile(filepath);
 }
 
 const readConfigJS = makeStrongCache((filepath, cache) => {
@@ -96,7 +103,10 @@ const readConfigJS = makeStrongCache((filepath, cache) => {
   try {
     // $FlowIssue
     const configModule = (require(filepath): mixed);
-    options = configModule && configModule.__esModule ? (configModule.default || undefined) : configModule;
+    options =
+      configModule && configModule.__esModule
+        ? configModule.default || undefined
+        : configModule;
   } catch (err) {
     err.message = `${filepath}: Error while loading config - ${err.message}`;
     throw err;
@@ -113,7 +123,9 @@ const readConfigJS = makeStrongCache((filepath, cache) => {
   }
 
   if (!options || typeof options !== "object" || Array.isArray(options)) {
-    throw new Error(`${filepath}: Configuration should be an exported JavaScript object.`);
+    throw new Error(
+      `${filepath}: Configuration should be an exported JavaScript object.`,
+    );
   }
 
   return {
@@ -144,8 +156,12 @@ const readConfigFile = makeStaticFileCache((filepath, content) => {
     if (!options) throw new Error(`${filepath}: No config detected`);
   }
 
-  if (typeof options !== "object") throw new Error(`${filepath}: Config returned typeof ${typeof options}`);
+  if (typeof options !== "object") {
-  if (Array.isArray(options)) throw new Error(`${filepath}: Expected config object but found array`);
+    throw new Error(`${filepath}: Config returned typeof ${typeof options}`);
+  }
+  if (Array.isArray(options)) {
+    throw new Error(`${filepath}: Expected config object but found array`);
+  }
 
   return {
     filepath,
@@ -157,8 +173,8 @@ const readConfigFile = makeStaticFileCache((filepath, content) => {
 const readIgnoreConfig = makeStaticFileCache((filepath, content) => {
   const ignore = content
     .split("\n")
-    .map((line) => line.replace(/#(.*?)$/, "").trim())
+    .map(line => line.replace(/#(.*?)$/, "").trim())
-    .filter((line) => !!line);
+    .filter(line => !!line);
 
   return {
     filepath,
@@ -167,7 +183,7 @@ const readIgnoreConfig = makeStaticFileCache((filepath, content) => {
   };
 });
 
-function makeStaticFileCache<T>(fn: (string, string) => T): (string) => T|null {
+function makeStaticFileCache<T>(fn: (string, string) => T): string => T | null {
   return makeStrongCache((filepath, cache) => {
     if (cache.invalidate(() => fileMtime(filepath)) === null) {
       cache.forever();
@@ -178,7 +194,7 @@ function makeStaticFileCache<T>(fn: (string, string) => T): (string) => T|null {
   });
 }
 
-function fileMtime(filepath: string): number|null {
+function fileMtime(filepath: string): number | null {
   try {
     return +fs.statSync(filepath).mtime;
   } catch (e) {

packages/babel-core/src/config/loading/files/index-browser.js

@@ -16,27 +16,47 @@ export function loadConfig(name: string, dirname: string): ConfigFile {
 }
 
 // eslint-disable-next-line no-unused-vars
-export function resolvePlugin(name: string, dirname: string): string|null {
+export function resolvePlugin(name: string, dirname: string): string | null {
   return null;
 }
 
 // eslint-disable-next-line no-unused-vars
-export function resolvePreset(name: string, dirname: string): string|null {
+export function resolvePreset(name: string, dirname: string): string | null {
   return null;
 }
 
-export function loadPlugin(name: string, dirname: string): { filepath: string, value: mixed } {
+export function loadPlugin(
-  throw new Error(`Cannot load plugin ${name} relative to ${dirname} in a browser`);
+  name: string,
+  dirname: string,
+): { filepath: string, value: mixed } {
+  throw new Error(
+    `Cannot load plugin ${name} relative to ${dirname} in a browser`,
+  );
 }
 
-export function loadPreset(name: string, dirname: string): { filepath: string, value: mixed } {
+export function loadPreset(
-  throw new Error(`Cannot load preset ${name} relative to ${dirname} in a browser`);
+  name: string,
+  dirname: string,
+): { filepath: string, value: mixed } {
+  throw new Error(
+    `Cannot load preset ${name} relative to ${dirname} in a browser`,
+  );
 }
 
-export function loadParser(name: string, dirname: string): { filepath: string, value: Function } {
+export function loadParser(
-  throw new Error(`Cannot load parser ${name} relative to ${dirname} in a browser`);
+  name: string,
+  dirname: string,
+): { filepath: string, value: Function } {
+  throw new Error(
+    `Cannot load parser ${name} relative to ${dirname} in a browser`,
+  );
 }
 
-export function loadGenerator(name: string, dirname: string): { filepath: string, value: Function } {
+export function loadGenerator(
-  throw new Error(`Cannot load generator ${name} relative to ${dirname} in a browser`);
+  name: string,
+  dirname: string,
+): { filepath: string, value: Function } {
+  throw new Error(
+    `Cannot load generator ${name} relative to ${dirname} in a browser`,
+  );
 }

packages/babel-core/src/config/loading/files/index.js

@@ -5,7 +5,7 @@ import typeof * as indexType from "./index";
 
 // Kind of gross, but essentially asserting that the exports of this module are the same as the
 // exports of index-browser, since this file may be replaced at bundle time with index-browser.
-((({}: any) : $Exact<indexBrowserType>): $Exact<indexType>);
+((({}: any): $Exact<indexBrowserType>): $Exact<indexType>);
 
 export * from "./configuration";
 export * from "./plugins";

packages/babel-core/src/config/loading/files/plugins.js

@@ -15,17 +15,22 @@ const BABEL_PRESET_ORG_RE = /^(@babel[/\/])(?!preset-|[^/\/]+[/\/])/;
 const OTHER_PLUGIN_ORG_RE = /^(@(?!babel[/\/])[^/\/]+[/\/])(?!babel-plugin-|[^/\/]+[/\/])/;
 const OTHER_PRESET_ORG_RE = /^(@(?!babel[/\/])[^/\/]+[/\/])(?!babel-preset-|[^/\/]+[/\/])/;
 
-export function resolvePlugin(name: string, dirname: string): string|null {
+export function resolvePlugin(name: string, dirname: string): string | null {
   return resolveStandardizedName("plugin", name, dirname);
 }
 
-export function resolvePreset(name: string, dirname: string): string|null {
+export function resolvePreset(name: string, dirname: string): string | null {
   return resolveStandardizedName("preset", name, dirname);
 }
 
-export function loadPlugin(name: string, dirname: string): { filepath: string, value: mixed } {
+export function loadPlugin(
+  name: string,
+  dirname: string,
+): { filepath: string, value: mixed } {
   const filepath = resolvePlugin(name, dirname);
-  if (!filepath) throw new Error(`Plugin ${name} not found relative to ${dirname}`);
+  if (!filepath) {
+    throw new Error(`Plugin ${name} not found relative to ${dirname}`);
+  }
 
   return {
     filepath,
@@ -33,9 +38,14 @@ export function loadPlugin(name: string, dirname: string): { filepath: string, v
   };
 }
 
-export function loadPreset(name: string, dirname: string): { filepath: string, value: mixed } {
+export function loadPreset(
+  name: string,
+  dirname: string,
+): { filepath: string, value: mixed } {
   const filepath = resolvePreset(name, dirname);
-  if (!filepath) throw new Error(`Preset ${name} not found relative to ${dirname}`);
+  if (!filepath) {
+    throw new Error(`Preset ${name} not found relative to ${dirname}`);
+  }
 
   return {
     filepath,
@@ -43,16 +53,23 @@ export function loadPreset(name: string, dirname: string): { filepath: string, v
   };
 }
 
-export function loadParser(name: string, dirname: string): { filepath: string, value: Function } {
+export function loadParser(
+  name: string,
+  dirname: string,
+): { filepath: string, value: Function } {
   const filepath = resolve.sync(name, { basedir: dirname });
 
   const mod = requireModule(filepath);
 
   if (!mod) {
-    throw new Error(`Parser ${name} relative to ${dirname} does not export an object`);
+    throw new Error(
+      `Parser ${name} relative to ${dirname} does not export an object`,
+    );
   }
   if (typeof mod.parse !== "function") {
-    throw new Error(`Parser ${name} relative to ${dirname} does not export a .parse function`);
+    throw new Error(
+      `Parser ${name} relative to ${dirname} does not export a .parse function`,
+    );
   }
 
   return {
@@ -61,16 +78,23 @@ export function loadParser(name: string, dirname: string): { filepath: string, v
   };
 }
 
-export function loadGenerator(name: string, dirname: string): { filepath: string, value: Function } {
+export function loadGenerator(
+  name: string,
+  dirname: string,
+): { filepath: string, value: Function } {
   const filepath = resolve.sync(name, { basedir: dirname });
 
   const mod = requireModule(filepath);
 
   if (!mod) {
-    throw new Error(`Generator ${name} relative to ${dirname} does not export an object`);
+    throw new Error(
+      `Generator ${name} relative to ${dirname} does not export an object`,
+    );
   }
   if (typeof mod.print !== "function") {
-    throw new Error(`Generator ${name} relative to ${dirname} does not export a .print function`);
+    throw new Error(
+      `Generator ${name} relative to ${dirname} does not export a .print function`,
+    );
   }
 
   return {
@@ -79,24 +103,39 @@ export function loadGenerator(name: string, dirname: string): { filepath: string
   };
 }
 
-function standardizeName(type: "plugin"|"preset", name: string) {
+function standardizeName(type: "plugin" | "preset", name: string) {
   // Let absolute and relative paths through.
   if (path.isAbsolute(name)) return name;
 
   const isPreset = type === "preset";
 
-  return name
+  return (
+    name
       // foo -> babel-preset-foo
-    .replace(isPreset ? BABEL_PRESET_PREFIX_RE : BABEL_PLUGIN_PREFIX_RE, `babel-${type}-`)
+      .replace(
+        isPreset ? BABEL_PRESET_PREFIX_RE : BABEL_PLUGIN_PREFIX_RE,
+        `babel-${type}-`,
+      )
       // @babel/es2015 -> @babel/preset-es2015
-    .replace(isPreset ? BABEL_PRESET_ORG_RE : BABEL_PLUGIN_ORG_RE, `$1${type}-`)
+      .replace(
+        isPreset ? BABEL_PRESET_ORG_RE : BABEL_PLUGIN_ORG_RE,
+        `$1${type}-`,
+      )
       // @foo/mypreset -> @foo/babel-preset-mypreset
-    .replace(isPreset ? OTHER_PRESET_ORG_RE : OTHER_PLUGIN_ORG_RE, `$1babel-${type}-`)
+      .replace(
+        isPreset ? OTHER_PRESET_ORG_RE : OTHER_PLUGIN_ORG_RE,
+        `$1babel-${type}-`,
+      )
       // module:mypreset -> mypreset
-    .replace(EXACT_RE, "");
+      .replace(EXACT_RE, "")
+  );
 }
 
-function resolveStandardizedName(type: "plugin"|"preset", name: string, dirname: string = process.cwd()) {
+function resolveStandardizedName(
+  type: "plugin" | "preset",
+  name: string,
+  dirname: string = process.cwd(),
+) {
   const standardizedName = standardizeName(type, name);
 
   try {
@@ -109,7 +148,7 @@ function resolveStandardizedName(type: "plugin"|"preset", name: string, dirname:
       try {
         resolve.sync(name, { basedir: dirname });
         resolvedOriginal = true;
-      } catch (e2) { }
+      } catch (e2) {}
 
       if (resolvedOriginal) {
         // eslint-disable-next-line max-len
@@ -119,9 +158,11 @@ function resolveStandardizedName(type: "plugin"|"preset", name: string, dirname:
 
     let resolvedBabel = false;
     try {
-      resolve.sync(standardizeName(type, "@babel/" + name), { basedir: dirname });
+      resolve.sync(standardizeName(type, "@babel/" + name), {
+        basedir: dirname,
+      });
       resolvedBabel = true;
-    } catch (e2) { }
+    } catch (e2) {}
 
     if (resolvedBabel) {
       // eslint-disable-next-line max-len
@@ -133,7 +174,7 @@ function resolveStandardizedName(type: "plugin"|"preset", name: string, dirname:
     try {
       resolve.sync(standardizeName(oppositeType, name), { basedir: dirname });
       resolvedOppositeType = true;
-    } catch (e2) { }
+    } catch (e2) {}
 
     if (resolvedOppositeType) {
       // eslint-disable-next-line max-len

packages/babel-core/src/config/option-manager.js

@@ -11,14 +11,19 @@ import path from "path";
 import traverse from "babel-traverse";
 import clone from "lodash/clone";
 
-import { loadPlugin, loadPreset, loadParser, loadGenerator } from "./loading/files";
+import {
+  loadPlugin,
+  loadPreset,
+  loadParser,
+  loadGenerator,
+} from "./loading/files";
 
 type MergeOptions = {
-  +type: "arguments"|"options"|"preset",
+  +type: "arguments" | "options" | "preset",
   options: {},
   alias: string,
   loc: string,
-  dirname: string
+  dirname: string,
 };
 
 const optionNames = new Set([
@@ -74,8 +79,8 @@ const ALLOWED_PLUGIN_KEYS = new Set([
 
 export default function manageOptions(opts: {}): {
   options: Object,
-  passes: Array<Array<[ Plugin, ?{} ]>>,
+  passes: Array<Array<[Plugin, ?{}]>>,
-}|null {
+} | null {
   return new OptionManager().init(opts);
 }
 
@@ -100,9 +105,12 @@ class OptionManager {
   mergeOptions(config: MergeOptions, pass?: Array<[Plugin, ?{}]>) {
     const result = loadConfig(config);
 
-    const plugins = result.plugins.map((descriptor) => loadPluginDescriptor(descriptor));
+    const plugins = result.plugins.map(descriptor =>
-    const presets = result.presets.map((descriptor) => loadPresetDescriptor(descriptor));
+      loadPluginDescriptor(descriptor),
-
+    );
+    const presets = result.presets.map(descriptor =>
+      loadPresetDescriptor(descriptor),
+    );
 
     if (
       config.options.passPerPreset != null &&
@@ -148,7 +156,8 @@ class OptionManager {
       // There are a few case where thrown errors will try to annotate themselves multiple times, so
       // to keep things simple we just bail out if re-wrapping the message.
       if (!/^\[BABEL\]/.test(e.message)) {
-        const filename = typeof opts.filename === "string" ? opts.filename : null;
+        const filename =
+          typeof opts.filename === "string" ? opts.filename : null;
         e.message = `[BABEL] ${filename || "unknown"}: ${e.message}`;
       }
 
@@ -160,9 +169,10 @@ class OptionManager {
     // Tack the passes onto the object itself so that, if this object is passed back to Babel a second time,
     // it will be in the right structure to not change behavior.
     opts.plugins = this.passes[0];
-    opts.presets = this.passes.slice(1)
+    opts.presets = this.passes
-      .filter((plugins) => plugins.length > 0)
+      .slice(1)
-      .map((plugins) => ({ plugins }));
+      .filter(plugins => plugins.length > 0)
+      .map(plugins => ({ plugins }));
 
     if (opts.inputSourceMap) {
       opts.sourceMaps = true;
@@ -199,7 +209,7 @@ class OptionManager {
 }
 
 type BasicDescriptor = {
-  value: {}|Function,
+  value: {} | Function,
   options: ?{},
   dirname: string,
   alias: string,
@@ -209,19 +219,28 @@ type BasicDescriptor = {
 /**
  * Load and validate the given config into a set of options, plugins, and presets.
  */
-function loadConfig(config): {
+function loadConfig(
+  config,
+): {
   options: {},
   plugins: Array<BasicDescriptor>,
   presets: Array<BasicDescriptor>,
 } {
   const options = normalizeOptions(config);
 
-  if (config.options.plugins != null && !Array.isArray(config.options.plugins)) {
+  if (
+    config.options.plugins != null &&
+    !Array.isArray(config.options.plugins)
+  ) {
     throw new Error(".plugins should be an array, null, or undefined");
   }
 
   const plugins = (config.options.plugins || []).map((plugin, index) => {
-    const { filepath, value, options } = normalizePair(plugin, loadPlugin, config.dirname);
+    const { filepath, value, options } = normalizePair(
+      plugin,
+      loadPlugin,
+      config.dirname,
+    );
 
     return {
       alias: filepath || `${config.loc}$${index}`,
@@ -232,12 +251,19 @@ function loadConfig(config): {
     };
   });
 
-  if (config.options.presets != null && !Array.isArray(config.options.presets)) {
+  if (
+    config.options.presets != null &&
+    !Array.isArray(config.options.presets)
+  ) {
     throw new Error(".presets should be an array, null, or undefined");
   }
 
   const presets = (config.options.presets || []).map((preset, index) => {
-    const { filepath, value, options } = normalizePair(preset, loadPreset, config.dirname);
+    const { filepath, value, options } = normalizePair(
+      preset,
+      loadPreset,
+      config.dirname,
+    );
 
     return {
       alias: filepath || `${config.loc}$${index}`,
@@ -255,7 +281,9 @@ function loadConfig(config): {
  * Load a generic plugin/preset from the given descriptor loaded from the config object.
  */
 function loadDescriptor(descriptor, skipOptions) {
-  if (typeof descriptor.value !== "function") return { value: descriptor.value, descriptor };
+  if (typeof descriptor.value !== "function") {
+    return { value: descriptor.value, descriptor };
+  }
 
   const { value, options } = descriptor;
   let item;
@@ -266,7 +294,9 @@ function loadDescriptor(descriptor, skipOptions) {
       item = value(context, options, { dirname: descriptor.dirname });
     }
   } catch (e) {
-    if (descriptor.alias) e.message += ` (While processing: ${JSON.stringify(descriptor.alias)})`;
+    if (descriptor.alias) {
+      e.message += ` (While processing: ${JSON.stringify(descriptor.alias)})`;
+    }
     throw e;
   }
 
@@ -282,26 +312,37 @@ function loadDescriptor(descriptor, skipOptions) {
  */
 const PLUGIN_CACHE = new WeakMap();
 function loadPluginDescriptor(descriptor) {
-  if (descriptor.value instanceof Plugin) return [ descriptor.value, descriptor.options ];
+  if (descriptor.value instanceof Plugin) {
+    return [descriptor.value, descriptor.options];
+  }
 
   let result = PLUGIN_CACHE.get(descriptor.value);
   if (!result) {
-    result = instantiatePlugin(loadDescriptor(descriptor, true /* skipOptions */));
+    result = instantiatePlugin(
+      loadDescriptor(descriptor, true /* skipOptions */),
+    );
     PLUGIN_CACHE.set(descriptor.value, result);
   }
 
-  return [ result, descriptor.options];
+  return [result, descriptor.options];
 }
 
 function instantiatePlugin({ value: pluginObj, descriptor }) {
-  Object.keys(pluginObj).forEach((key) => {
+  Object.keys(pluginObj).forEach(key => {
     if (!ALLOWED_PLUGIN_KEYS.has(key)) {
-      throw new Error(messages.get("pluginInvalidProperty", descriptor.alias, key));
+      throw new Error(
+        messages.get("pluginInvalidProperty", descriptor.alias, key),
+      );
     }
   });
-  if (pluginObj.visitor && (pluginObj.visitor.enter || pluginObj.visitor.exit)) {
+  if (
-    throw new Error("Plugins aren't allowed to specify catch-all enter/exit handlers. " +
+    pluginObj.visitor &&
-      "Please target individual nodes.");
+    (pluginObj.visitor.enter || pluginObj.visitor.exit)
+  ) {
+    throw new Error(
+      "Plugins aren't allowed to specify catch-all enter/exit handlers. " +
+        "Please target individual nodes.",
+    );
   }
 
   const plugin = Object.assign({}, pluginObj, {
@@ -325,8 +366,14 @@ function instantiatePlugin({ value: pluginObj, descriptor }) {
 
     plugin.pre = chain(inherits.pre, plugin.pre);
     plugin.post = chain(inherits.post, plugin.post);
-    plugin.manipulateOptions = chain(inherits.manipulateOptions, plugin.manipulateOptions);
+    plugin.manipulateOptions = chain(
-    plugin.visitor = traverse.visitors.merge([inherits.visitor, plugin.visitor]);
+      inherits.manipulateOptions,
+      plugin.manipulateOptions,
+    );
+    plugin.visitor = traverse.visitors.merge([
+      inherits.visitor,
+      plugin.visitor,
+    ]);
   }
 
   return new Plugin(plugin, descriptor.alias);
@@ -371,10 +418,18 @@ function normalizeOptions(config) {
   }
 
   if (type === "preset") {
-    if (options.only !== undefined) throw new Error(`${alias}.only is not supported in a preset`);
+    if (options.only !== undefined) {
-    if (options.ignore !== undefined) throw new Error(`${alias}.ignore is not supported in a preset`);
+      throw new Error(`${alias}.only is not supported in a preset`);
-    if (options.extends !== undefined) throw new Error(`${alias}.extends is not supported in a preset`);
+    }
-    if (options.env !== undefined) throw new Error(`${alias}.env is not supported in a preset`);
+    if (options.ignore !== undefined) {
+      throw new Error(`${alias}.ignore is not supported in a preset`);
+    }
+    if (options.extends !== undefined) {
+      throw new Error(`${alias}.extends is not supported in a preset`);
+    }
+    if (options.env !== undefined) {
+      throw new Error(`${alias}.env is not supported in a preset`);
+    }
   }
 
   if (options.sourceMap !== undefined) {
@@ -390,7 +445,10 @@ function normalizeOptions(config) {
     // check for an unknown option
     if (!optionNames.has(key)) {
       if (removed[key]) {
-        throw new ReferenceError(`Using removed Babel 5 option: ${alias}.${key} - ${removed[key].message}`);
+        throw new ReferenceError(
+          `Using removed Babel 5 option: ${alias}.${key} - ${removed[key]
+            .message}`,
+        );
       } else {
         // eslint-disable-next-line max-len
         const unknownOptErr = `Unknown option: ${alias}.${key}. Check out http://babeljs.io/docs/usage/options/ for more information about options.`;
@@ -402,12 +460,21 @@ function normalizeOptions(config) {
 
   if (options.parserOpts && typeof options.parserOpts.parser === "string") {
     options.parserOpts = Object.assign({}, options.parserOpts);
-    options.parserOpts.parser = loadParser(options.parserOpts.parser, config.dirname).value;
+    options.parserOpts.parser = loadParser(
+      options.parserOpts.parser,
+      config.dirname,
+    ).value;
   }
 
-  if (options.generatorOpts && typeof options.generatorOpts.generator === "string") {
+  if (
+    options.generatorOpts &&
+    typeof options.generatorOpts.generator === "string"
+  ) {
     options.generatorOpts = Object.assign({}, options.generatorOpts);
-    options.generatorOpts.generator = loadGenerator(options.generatorOpts.generator, config.dirname).value;
+    options.generatorOpts.generator = loadGenerator(
+      options.generatorOpts.generator,
+      config.dirname,
+    ).value;
   }
 
   delete options.passPerPreset;
@@ -420,16 +487,22 @@ function normalizeOptions(config) {
 /**
  * Given a plugin/preset item, resolve it into a standard format.
  */
-function normalizePair(pair: mixed, resolver, dirname): {
+function normalizePair(
-  filepath: string|null,
+  pair: mixed,
-  value: {}|Function,
+  resolver,
+  dirname,
+): {
+  filepath: string | null,
+  value: {} | Function,
   options: ?{},
 } {
   let options;
   let value = pair;
   if (Array.isArray(pair)) {
     if (pair.length > 2) {
-      throw new Error(`Unexpected extra options ${JSON.stringify(pair.slice(2))}.`);
+      throw new Error(
+        `Unexpected extra options ${JSON.stringify(pair.slice(2))}.`,
+      );
     }
 
     [value, options] = pair;
@@ -437,10 +510,7 @@ function normalizePair(pair: mixed, resolver, dirname): {
 
   let filepath = null;
   if (typeof value === "string") {
-    ({
+    ({ filepath, value } = resolver(value, dirname));
-      filepath,
-      value,
-    } = resolver(value, dirname));
   }
 
   if (!value) {
@@ -456,11 +526,15 @@ function normalizePair(pair: mixed, resolver, dirname): {
   }
 
   if (typeof value !== "object" && typeof value !== "function") {
-    throw new Error(`Unsupported format: ${typeof value}. Expected an object or a function.`);
+    throw new Error(
+      `Unsupported format: ${typeof value}. Expected an object or a function.`,
+    );
   }
 
   if (options != null && typeof options !== "object") {
-    throw new Error("Plugin/Preset options must be an object, null, or undefined");
+    throw new Error(
+      "Plugin/Preset options must be an object, null, or undefined",
+    );
   }
 
   return { filepath, value, options };

packages/babel-core/src/config/plugin.js

@@ -5,8 +5,13 @@ export default class Plugin {
     if (plugin.name != null && typeof plugin.name !== "string") {
       throw new Error("Plugin .name must be a string, null, or undefined");
     }
-    if (plugin.manipulateOptions != null && typeof plugin.manipulateOptions !== "function") {
+    if (
-      throw new Error("Plugin .manipulateOptions must be a function, null, or undefined");
+      plugin.manipulateOptions != null &&
+      typeof plugin.manipulateOptions !== "function"
+    ) {
+      throw new Error(
+        "Plugin .manipulateOptions must be a function, null, or undefined",
+      );
     }
     if (plugin.post != null && typeof plugin.post !== "function") {
       throw new Error("Plugin .post must be a function, null, or undefined");

packages/babel-core/src/config/removed.js

@@ -2,52 +2,58 @@
 /* eslint max-len: "off" */
 
 export default {
-  "auxiliaryComment": {
+  auxiliaryComment: {
-    "message": "Use `auxiliaryCommentBefore` or `auxiliaryCommentAfter`",
+    message: "Use `auxiliaryCommentBefore` or `auxiliaryCommentAfter`",
   },
-  "blacklist": {
+  blacklist: {
-    "message": "Put the specific transforms you want in the `plugins` option",
+    message: "Put the specific transforms you want in the `plugins` option",
   },
-  "breakConfig": {
+  breakConfig: {
-    "message": "This is not a necessary option in Babel 6",
+    message: "This is not a necessary option in Babel 6",
   },
-  "experimental": {
+  experimental: {
-    "message": "Put the specific transforms you want in the `plugins` option",
+    message: "Put the specific transforms you want in the `plugins` option",
   },
-  "externalHelpers": {
+  externalHelpers: {
-    "message": "Use the `external-helpers` plugin instead. Check out http://babeljs.io/docs/plugins/external-helpers/",
+    message:
+      "Use the `external-helpers` plugin instead. Check out http://babeljs.io/docs/plugins/external-helpers/",
   },
-  "extra": {
+  extra: {
-    "message": "",
+    message: "",
   },
-  "jsxPragma": {
+  jsxPragma: {
-    "message": "use the `pragma` option in the `react-jsx` plugin . Check out http://babeljs.io/docs/plugins/transform-react-jsx/",
+    message:
+      "use the `pragma` option in the `react-jsx` plugin . Check out http://babeljs.io/docs/plugins/transform-react-jsx/",
   },
   // "keepModuleIdExtensions": {
   //   "message": ""
   // },
-  "loose": {
+  loose: {
-    "message": "Specify the `loose` option for the relevant plugin you are using or use a preset that sets the option.",
+    message:
+      "Specify the `loose` option for the relevant plugin you are using or use a preset that sets the option.",
   },
-  "metadataUsedHelpers": {
+  metadataUsedHelpers: {
-    "message": "Not required anymore as this is enabled by default",
+    message: "Not required anymore as this is enabled by default",
   },
-  "modules": {
+  modules: {
-    "message": "Use the corresponding module transform plugin in the `plugins` option. Check out http://babeljs.io/docs/plugins/#modules",
+    message:
+      "Use the corresponding module transform plugin in the `plugins` option. Check out http://babeljs.io/docs/plugins/#modules",
   },
-  "nonStandard": {
+  nonStandard: {
-    "message": "Use the `react-jsx` and `flow-strip-types` plugins to support JSX and Flow. Also check out the react preset http://babeljs.io/docs/plugins/preset-react/",
+    message:
+      "Use the `react-jsx` and `flow-strip-types` plugins to support JSX and Flow. Also check out the react preset http://babeljs.io/docs/plugins/preset-react/",
   },
-  "optional": {
+  optional: {
-    "message": "Put the specific transforms you want in the `plugins` option",
+    message: "Put the specific transforms you want in the `plugins` option",
   },
-  "sourceMapName": {
+  sourceMapName: {
-    "message": "Use the `sourceMapTarget` option",
+    message: "Use the `sourceMapTarget` option",
   },
-  "stage": {
+  stage: {
-    "message": "Check out the corresponding stage-x presets http://babeljs.io/docs/plugins/#presets",
+    message:
+      "Check out the corresponding stage-x presets http://babeljs.io/docs/plugins/#presets",
   },
-  "whitelist": {
+  whitelist: {
-    "message": "Put the specific transforms you want in the `plugins` option",
+    message: "Put the specific transforms you want in the `plugins` option",
   },
 };

packages/babel-core/src/index.js

@@ -12,7 +12,7 @@ export template from "babel-template";
 
 import loadConfig from "./config";
 
-export function loadOptions(opts): Object|null {
+export function loadOptions(opts): Object | null {
   const config = loadConfig(opts);
 
   return config ? config.options : null;
@@ -41,4 +41,10 @@ export {
  * Recommended set of compilable extensions. Not used in babel-core directly, but meant as
  * as an easy source for tooling making use of babel-core.
  */
-export const DEFAULT_EXTENSIONS = Object.freeze([".js", ".jsx", ".es6", ".es", ".mjs"]);
+export const DEFAULT_EXTENSIONS = Object.freeze([
+  ".js",
+  ".jsx",
+  ".es6",
+  ".es",
+  ".mjs",
+]);

packages/babel-core/src/tools/build-external-helpers.js

@@ -20,17 +20,29 @@ const buildUmdWrapper = template(`
 
 function buildGlobal(namespace, builder) {
   const body = [];
-  const container = t.functionExpression(null, [t.identifier("global")], t.blockStatement(body));
+  const container = t.functionExpression(
+    null,
+    [t.identifier("global")],
+    t.blockStatement(body),
+  );
   const tree = t.program([
-    t.expressionStatement(t.callExpression(container, [helpers.get("selfGlobal")]))]);
+    t.expressionStatement(
+      t.callExpression(container, [helpers.get("selfGlobal")]),
+    ),
+  ]);
 
-  body.push(t.variableDeclaration("var", [
+  body.push(
+    t.variableDeclaration("var", [
       t.variableDeclarator(
         namespace,
-      t.assignmentExpression("=", t.memberExpression(t.identifier("global"), namespace),
+        t.assignmentExpression(
-        t.objectExpression([]))
+          "=",
+          t.memberExpression(t.identifier("global"), namespace),
+          t.objectExpression([]),
         ),
-  ]));
+      ),
+    ]),
+  );
 
   builder(body);
 
@@ -39,9 +51,11 @@ function buildGlobal(namespace, builder) {
 
 function buildUmd(namespace, builder) {
   const body = [];
-  body.push(t.variableDeclaration("var", [
+  body.push(
+    t.variableDeclaration("var", [
       t.variableDeclarator(namespace, t.identifier("global")),
-  ]));
+    ]),
+  );
 
   builder(body);
 
@@ -51,7 +65,7 @@ function buildUmd(namespace, builder) {
       BROWSER_ARGUMENTS: t.assignmentExpression(
         "=",
         t.memberExpression(t.identifier("root"), namespace),
-        t.objectExpression([])
+        t.objectExpression([]),
       ),
       COMMON_ARGUMENTS: t.identifier("exports"),
       AMD_ARGUMENTS: t.arrayExpression([t.stringLiteral("exports")]),
@@ -63,31 +77,39 @@ function buildUmd(namespace, builder) {
 
 function buildVar(namespace, builder) {
   const body = [];
-  body.push(t.variableDeclaration("var", [
+  body.push(
+    t.variableDeclaration("var", [
       t.variableDeclarator(namespace, t.objectExpression([])),
-  ]));
+    ]),
+  );
   builder(body);
   body.push(t.expressionStatement(namespace));
   return t.program(body);
 }
 
 function buildHelpers(body, namespace, whitelist) {
-  helpers.list.forEach(function (name) {
+  helpers.list.forEach(function(name) {
     if (whitelist && whitelist.indexOf(name) < 0) return;
 
     const key = t.identifier(name);
-    body.push(t.expressionStatement(
+    body.push(
-      t.assignmentExpression("=", t.memberExpression(namespace, key), helpers.get(name))
+      t.expressionStatement(
-    ));
+        t.assignmentExpression(
+          "=",
+          t.memberExpression(namespace, key),
+          helpers.get(name),
+        ),
+      ),
+    );
   });
 }
-export default function (
+export default function(
   whitelist?: Array<string>,
   outputType: "global" | "umd" | "var" = "global",
 ) {
   const namespace = t.identifier("babelHelpers");
 
-  const builder = function (body) {
+  const builder = function(body) {
     return buildHelpers(body, namespace, whitelist);
   };
 

packages/babel-core/src/transformation/file/index.js

@@ -45,7 +45,7 @@ export default class File extends Store {
       // passed babel-core's export object, which loads this file, and this 'loadConfig' loading plugins.
       INTERNAL_PLUGINS = loadConfig({
         babelrc: false,
-        plugins: [ blockHoistPlugin ],
+        plugins: [blockHoistPlugin],
       }).passes[0];
     }
 
@@ -61,7 +61,7 @@ export default class File extends Store {
     };
 
     for (const pluginPairs of passes) {
-      for (const [ plugin ] of pluginPairs) {
+      for (const [plugin] of pluginPairs) {
         if (plugin.manipulateOptions) {
           plugin.manipulateOptions(this.opts, this.parserOpts, this);
         }
@@ -150,7 +150,7 @@ export default class File extends Store {
 
     if (opts.sourceRoot != null) {
       // remove sourceRoot from filename
-      const sourceRootRegEx = new RegExp("^" + opts.sourceRoot + "\/?");
+      const sourceRootRegEx = new RegExp("^" + opts.sourceRoot + "/?");
       filenameRelative = filenameRelative.replace(sourceRootRegEx, "");
     }
 
@@ -172,17 +172,25 @@ export default class File extends Store {
 
   resolveModuleSource(source: string): string {
     const resolveModuleSource = this.opts.resolveModuleSource;
-    if (resolveModuleSource) source = resolveModuleSource(source, this.opts.filename);
+    if (resolveModuleSource) {
+      source = resolveModuleSource(source, this.opts.filename);
+    }
     return source;
   }
 
-  addImport(source: string, imported: string, name?: string = imported): Object {
+  addImport(
+    source: string,
+    imported: string,
+    name?: string = imported,
+  ): Object {
     const alias = `${source}:${imported}`;
     let id = this.dynamicImportIds[alias];
 
     if (!id) {
       source = this.resolveModuleSource(source);
-      id = this.dynamicImportIds[alias] = this.scope.generateUidIdentifier(name);
+      id = this.dynamicImportIds[alias] = this.scope.generateUidIdentifier(
+        name,
+      );
 
       const specifiers = [];
 
@@ -222,7 +230,9 @@ export default class File extends Store {
     }
 
     const ref = getHelper(name);
-    const uid = this.declarations[name] = this.scope.generateUidIdentifier(name);
+    const uid = (this.declarations[name] = this.scope.generateUidIdentifier(
+      name,
+    ));
 
     if (t.isFunctionExpression(ref) && !ref.id) {
       ref.body._compact = true;
@@ -257,7 +267,9 @@ export default class File extends Store {
     const declar = this.declarations[name];
     if (declar) return declar;
 
-    const uid = this.declarations[name] = this.scope.generateUidIdentifier("templateObject");
+    const uid = (this.declarations[name] = this.scope.generateUidIdentifier(
+      "templateObject",
+    ));
 
     const helperId = this.addHelper(helperName);
     const init = t.callExpression(helperId, [strings, raw]);
@@ -270,7 +282,11 @@ export default class File extends Store {
     return uid;
   }
 
-  buildCodeFrameError(node: Object, msg: string, Error: typeof Error = SyntaxError): Error {
+  buildCodeFrameError(
+    node: Object,
+    msg: string,
+    Error: typeof Error = SyntaxError,
+  ): Error {
     const loc = node && (node.loc || node._loc);
 
     const err = new Error(msg);
@@ -280,7 +296,8 @@ export default class File extends Store {
     } else {
       traverse(node, errorVisitor, this.scope, err);
 
-      err.message += " (This is an error on an internal node. Probably an internal error";
+      err.message +=
+        " (This is an error on an internal node. Probably an internal error";
 
       if (err.loc) {
         err.message += ". Location has been estimated.";
@@ -308,7 +325,7 @@ export default class File extends Store {
       // single source file to a single output file.
       const source = outputMapConsumer.sources[0];
 
-      inputMapConsumer.eachMapping(function (mapping) {
+      inputMapConsumer.eachMapping(function(mapping) {
         const generatedPosition = outputMapConsumer.generatedPositionFor({
           line: mapping.generatedLine,
           column: mapping.generatedColumn,
@@ -318,7 +335,10 @@ export default class File extends Store {
           mergedGenerator.addMapping({
             source: mapping.source,
 
-            original: mapping.source == null ? null : {
+            original:
+              mapping.source == null
+                ? null
+                : {
                     line: mapping.originalLine,
                     column: mapping.originalColumn,
                   },
@@ -385,15 +405,15 @@ export default class File extends Store {
       const passes = [];
       const visitors = [];
 
-      for (const [ plugin, pluginOpts ] of pluginPairs.concat(INTERNAL_PLUGINS)) {
+      for (const [plugin, pluginOpts] of pluginPairs.concat(INTERNAL_PLUGINS)) {
         const pass = new PluginPass(this, plugin.key, pluginOpts);
 
-        passPairs.push([ plugin, pass ]);
+        passPairs.push([plugin, pass]);
         passes.push(pass);
         visitors.push(plugin.visitor);
       }
 
-      for (const [ plugin, pass ] of passPairs) {
+      for (const [plugin, pass] of passPairs) {
         const fn = plugin.pre;
         if (fn) fn.call(pass, this);
       }
@@ -401,16 +421,19 @@ export default class File extends Store {
       debug(this.opts, "Start transform traverse");
 
       // merge all plugin visitors into a single visitor
-      const visitor = traverse.visitors.merge(visitors, passes, this.opts.wrapPluginVisitorMethod);
+      const visitor = traverse.visitors.merge(
+        visitors,
+        passes,
+        this.opts.wrapPluginVisitorMethod,
+      );
       traverse(this.ast, visitor, this.scope);
 
       debug(this.opts, "End transform traverse");
 
-      for (const [ plugin, pass ] of passPairs) {
+      for (const [plugin, pass] of passPairs) {
         const fn = plugin.post;
         if (fn) fn.call(pass, this);
       }
-
     }
 
     return this.generate();
@@ -428,7 +451,7 @@ export default class File extends Store {
         err._babel = true;
       }
 
-      let message = err.message = `${this.opts.filename}: ${err.message}`;
+      let message = (err.message = `${this.opts.filename}: ${err.message}`);
 
       const loc = err.loc;
       if (loc) {
@@ -530,8 +553,11 @@ export default class File extends Store {
 
     debug(this.opts, "Generation start");
 
-    const _result = gen(ast, opts.generatorOpts ? Object.assign(opts, opts.generatorOpts) : opts,
+    const _result = gen(
-      this.code);
+      ast,
+      opts.generatorOpts ? Object.assign(opts, opts.generatorOpts) : opts,
+      this.code,
+    );
     result.code = _result.code;
     result.map = _result.map;
 

packages/babel-core/src/transformation/pipeline.js

@@ -5,7 +5,11 @@ import * as t from "babel-types";
 import File from "./file";
 import loadConfig from "../config";
 
-export function analyse(code: string, opts: Object = {}, visitor?: Object): ?BabelFileMetadata {
+export function analyse(
+  code: string,
+  opts: Object = {},
+  visitor?: Object,
+): ?BabelFileMetadata {
   opts.code = false;
   if (visitor) {
     opts.plugins = opts.plugins || [];
@@ -19,14 +23,18 @@ export function transform(code: string, opts?: Object): BabelFileResult {
   if (config === null) return null;
 
   const file = new File(config);
-  return file.wrap(code, function () {
+  return file.wrap(code, function() {
     file.addCode(code);
     file.parseCode(code);
     return file.transform();
   });
 }
 
-export function transformFromAst(ast: Object, code: string, opts: Object): BabelFileResult {
+export function transformFromAst(
+  ast: Object,
+  code: string,
+  opts: Object,
+): BabelFileResult {
   const config = loadConfig(opts);
   if (config === null) return null;
 
@@ -37,14 +45,18 @@ export function transformFromAst(ast: Object, code: string, opts: Object): Babel
   }
 
   const file = new File(config);
-  return file.wrap(code, function () {
+  return file.wrap(code, function() {
     file.addCode(code);
     file.addAst(ast);
     return file.transform();
   });
 }
 
-export function transformFile(filename: string, opts?: Object, callback: Function) {
+export function transformFile(
+  filename: string,
+  opts?: Object,
+  callback: Function,
+) {
   if (typeof opts === "function") {
     callback = opts;
     opts = {};
@@ -54,13 +66,13 @@ export function transformFile(filename: string, opts?: Object, callback: Functio
   const config = loadConfig(opts);
   if (config === null) return callback(null, null);
 
-  fs.readFile(filename, function (err, code) {
+  fs.readFile(filename, function(err, code) {
     let result;
 
     if (!err) {
       try {
         const file = new File(config);
-        result = file.wrap(code, function () {
+        result = file.wrap(code, function() {
           file.addCode(code);
           file.parseCode(code);
           return file.transform();
@@ -78,7 +90,10 @@ export function transformFile(filename: string, opts?: Object, callback: Functio
   });
 }
 
-export function transformFileSync(filename: string, opts?: Object = {}): string {
+export function transformFileSync(
+  filename: string,
+  opts?: Object = {},
+): string {
   opts.filename = filename;
   const config = loadConfig(opts);
   if (config === null) return null;
@@ -86,7 +101,7 @@ export function transformFileSync(filename: string, opts?: Object = {}): string
   const code = fs.readFileSync(filename, "utf8");
   const file = new File(config);
 
-  return file.wrap(code, function () {
+  return file.wrap(code, function() {
     file.addCode(code);
     file.parseCode(code);
     return file.transform();

packages/babel-core/test/api.js

@@ -17,7 +17,7 @@ function assertNotIgnored(result) {
 // shim
 function transformAsync(code, opts) {
   return {
-    then: function (resolve) {
+    then: function(resolve) {
       resolve(babel.transform(code, opts));
     },
   };
@@ -55,11 +55,14 @@ describe("parser and generator options", function() {
   it("experimental syntax", function() {
     const experimental = "var a: number = 1;";
 
-    assert.deepEqual(newTransform(experimental).ast, babel.transform(experimental, {
+    assert.deepEqual(
+      newTransform(experimental).ast,
+      babel.transform(experimental, {
         parserOpts: {
           plugins: ["flow"],
         },
-    }).ast);
+      }).ast,
+    );
     assert.equal(newTransform(experimental).code, experimental);
 
     function newTransformWithPlugins(string) {
@@ -74,126 +77,158 @@ describe("parser and generator options", function() {
       });
     }
 
-    assert.deepEqual(newTransformWithPlugins(experimental).ast, babel.transform(experimental, {
+    assert.deepEqual(
+      newTransformWithPlugins(experimental).ast,
+      babel.transform(experimental, {
         parserOpts: {
           plugins: ["flow"],
         },
-    }).ast);
+      }).ast,
+    );
     assert.equal(newTransformWithPlugins(experimental).code, experimental);
   });
 
   it("other options", function() {
     const experimental = "if (true) {\n  import a from 'a';\n}";
 
-    assert.notEqual(newTransform(experimental).ast, babel.transform(experimental, {
+    assert.notEqual(
+      newTransform(experimental).ast,
+      babel.transform(experimental, {
         parserOpts: {
           allowImportExportEverywhere: true,
         },
-    }).ast);
+      }).ast,
+    );
     assert.equal(newTransform(experimental).code, experimental);
   });
 });
 
-describe("api", function () {
+describe("api", function() {
-  it("analyze", function () {
+  it("analyze", function() {
     assert.equal(babel.analyse("foobar;").marked.length, 0);
 
-    assert.equal(babel.analyse("foobar;", {
+    assert.equal(
-      plugins: [new Plugin({
+      babel.analyse("foobar;", {
+        plugins: [
+          new Plugin({
             visitor: {
-          Program: function (path) {
+              Program: function(path) {
                 path.mark("category", "foobar");
               },
             },
-      })],
+          }),
-    }).marked[0].message, "foobar");
+        ],
+      }).marked[0].message,
+      "foobar",
+    );
 
-    assert.equal(babel.analyse("foobar;", {}, {
+    assert.equal(
-      Program: function (path) {
+      babel.analyse(
+        "foobar;",
+        {},
+        {
+          Program: function(path) {
             path.mark("category", "foobar");
           },
-    }).marked[0].message, "foobar");
-  });
-
-  it("exposes the resolvePlugin method", function() {
-    assert.throws(() => babel.resolvePlugin("nonexistent-plugin"),
-      /Cannot find module 'babel-plugin-nonexistent-plugin'/);
-  });
-
-  it("exposes the resolvePreset method", function() {
-    assert.throws(() => babel.resolvePreset("nonexistent-preset"),
-      /Cannot find module 'babel-preset-nonexistent-preset'/);
-  });
-
-  it("transformFile", function (done) {
-    babel.transformFile(__dirname + "/fixtures/api/file.js", {
-      babelrc: false,
-    }, function (err, res) {
-      if (err) return done(err);
-      assert.equal(res.code, "foo();");
-      done();
-    });
-  });
-
-  it("transformFileSync", function () {
-    assert.equal(babel.transformFileSync(__dirname + "/fixtures/api/file.js", {
-      babelrc: false,
-    }).code, "foo();");
-  });
-
-  it("options throw on falsy true", function () {
-    return assert.throws(
-      function () {
-        babel.transform("", {
-          plugins: [__dirname + "/../../babel-plugin-syntax-jsx", false],
-        });
         },
-      /Error: \[BABEL\] unknown: Unexpected falsy value: false/
+      ).marked[0].message,
+      "foobar",
     );
   });
 
-  it("options merge backwards", function () {
+  it("exposes the resolvePlugin method", function() {
+    assert.throws(
+      () => babel.resolvePlugin("nonexistent-plugin"),
+      /Cannot find module 'babel-plugin-nonexistent-plugin'/,
+    );
+  });
+
+  it("exposes the resolvePreset method", function() {
+    assert.throws(
+      () => babel.resolvePreset("nonexistent-preset"),
+      /Cannot find module 'babel-preset-nonexistent-preset'/,
+    );
+  });
+
+  it("transformFile", function(done) {
+    babel.transformFile(
+      __dirname + "/fixtures/api/file.js",
+      {
+        babelrc: false,
+      },
+      function(err, res) {
+        if (err) return done(err);
+        assert.equal(res.code, "foo();");
+        done();
+      },
+    );
+  });
+
+  it("transformFileSync", function() {
+    assert.equal(
+      babel.transformFileSync(__dirname + "/fixtures/api/file.js", {
+        babelrc: false,
+      }).code,
+      "foo();",
+    );
+  });
+
+  it("options throw on falsy true", function() {
+    return assert.throws(function() {
+      babel.transform("", {
+        plugins: [__dirname + "/../../babel-plugin-syntax-jsx", false],
+      });
+    }, /Error: \[BABEL\] unknown: Unexpected falsy value: false/);
+  });
+
+  it("options merge backwards", function() {
     return transformAsync("", {
       presets: [__dirname + "/../../babel-preset-es2015"],
       plugins: [__dirname + "/../../babel-plugin-syntax-jsx"],
-    }).then(function (result) {
+    }).then(function(result) {
-      assert.ok(result.options.plugins[0][0].manipulateOptions.toString().indexOf("jsx") >= 0);
+      assert.ok(
+        result.options.plugins[0][0].manipulateOptions
+          .toString()
+          .indexOf("jsx") >= 0,
+      );
     });
   });
 
-  it("option wrapPluginVisitorMethod", function () {
+  it("option wrapPluginVisitorMethod", function() {
     let calledRaw = 0;
     let calledIntercept = 0;
 
     babel.transform("function foo() { bar(foobar); }", {
-      wrapPluginVisitorMethod: function (pluginAlias, visitorType, callback) {
+      wrapPluginVisitorMethod: function(pluginAlias, visitorType, callback) {
         if (pluginAlias !== "foobar") {
           return callback;
         }
 
         assert.equal(visitorType, "enter");
 
-        return function () {
+        return function() {
           calledIntercept++;
           return callback.apply(this, arguments);
         };
       },
 
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           name: "foobar",
           visitor: {
-          "Program|Identifier": function () {
+            "Program|Identifier": function() {
               calledRaw++;
             },
           },
-      })],
+        }),
+      ],
     });
 
     assert.equal(calledRaw, 4);
     assert.equal(calledIntercept, 4);
   });
 
-  it("pass per preset", function () {
+  it("pass per preset", function() {
     let aliasBaseType = null;
 
     function execTest(passPerPreset) {
@@ -201,13 +236,15 @@ describe("api", function () {
         passPerPreset: passPerPreset,
         presets: [
           // First preset with our plugin, "before"
-          function () {
+          function() {
             return {
               plugins: [
                 new Plugin({
                   visitor: {
-                    Function: function (path) {
+                    Function: function(path) {
-                      const alias = path.scope.getProgramParent().path.get("body")[0].node;
+                      const alias = path.scope
+                        .getProgramParent()
+                        .path.get("body")[0].node;
                       if (!babel.types.isTypeAlias(alias)) return;
 
                       // In case of `passPerPreset` being `false`, the
@@ -230,11 +267,12 @@ describe("api", function () {
           require(__dirname + "/../../babel-preset-es2015"),
 
           // Third preset for Flow.
-          function () {
+          function() {
             return {
               plugins: [
                 require(__dirname + "/../../babel-plugin-syntax-flow"),
-                require(__dirname + "/../../babel-plugin-transform-flow-strip-types"),
+                require(__dirname +
+                  "/../../babel-plugin-transform-flow-strip-types"),
               ],
             };
           },
@@ -248,13 +286,16 @@ describe("api", function () {
 
     assert.equal(aliasBaseType, "NumberTypeAnnotation");
 
-    assert.deepEqual([
+    assert.deepEqual(
-      "\"use strict\";",
+      [
+        '"use strict";',
         "",
         "var x = function x(y) {",
         "  return y;",
         "};",
-    ].join("\n"), result.code);
+      ].join("\n"),
+      result.code,
+    );
 
     // 2. passPerPreset: false
 
@@ -264,14 +305,16 @@ describe("api", function () {
 
     assert.equal(aliasBaseType, null);
 
-    assert.deepEqual([
+    assert.deepEqual(
-      "\"use strict\";",
+      [
+        '"use strict";',
         "",
         "var x = function x(y) {",
         "  return y;",
         "};",
-    ].join("\n"), result.code);
+      ].join("\n"),
-
+      result.code,
+    );
   });
 
   it("complex plugin and preset ordering", function() {
@@ -279,7 +322,10 @@ describe("api", function () {
       return {
         visitor: {
           Program(path) {
-            path.pushContainer("body", babel.types.expressionStatement(babel.types.identifier(str)));
+            path.pushContainer(
+              "body",
+              babel.types.expressionStatement(babel.types.identifier(str)),
+            );
           },
         },
       };
@@ -290,32 +336,31 @@ describe("api", function () {
     }
 
     const result = babel.transform("", {
-      filename: path.join(__dirname, "fixtures", "config", "complex-plugin-config", "file.js"),
+      filename: path.join(
-      presets: [
+        __dirname,
-        pushPreset("argone"),
+        "fixtures",
-        pushPreset("argtwo"),
+        "config",
-      ],
+        "complex-plugin-config",
+        "file.js",
+      ),
+      presets: [pushPreset("argone"), pushPreset("argtwo")],
       env: {
         development: {
           passPerPreset: true,
-          presets: [
+          presets: [pushPreset("argthree"), pushPreset("argfour")],
-            pushPreset("argthree"),
-            pushPreset("argfour"),
-          ],
           env: {
             development: {
               passPerPreset: true,
-              presets: [
+              presets: [pushPreset("argfive"), pushPreset("argsix")],
-                pushPreset("argfive"),
-                pushPreset("argsix"),
-              ],
             },
           },
         },
       },
     });
 
-    assert.equal(result.code, [
+    assert.equal(
+      result.code,
+      [
         "argtwo;",
         "argone;",
         "eleven;",
@@ -342,13 +387,15 @@ describe("api", function () {
         "eight;",
         "nine;",
         "ten;",
-    ].join("\n"));
+      ].join("\n"),
+    );
   });
 
-  it("source map merging", function () {
+  it("source map merging", function() {
-    const result = babel.transform([
+    const result = babel.transform(
+      [
         /* eslint-disable max-len */
-      "function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError(\"Cannot call a class as a function\"); } }",
+        'function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }',
         "",
         "let Foo = function Foo() {",
         "  _classCallCheck(this, Foo);",
@@ -356,222 +403,278 @@ describe("api", function () {
         "",
         "//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZG91dCJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiOztJQUFNLEdBQUcsWUFBSCxHQUFHO3dCQUFILEdBQUciLCJmaWxlIjoidW5kZWZpbmVkIiwic291cmNlc0NvbnRlbnQiOlsiY2xhc3MgRm9vIHt9XG4iXX0=",
         /* eslint-enable max-len */
-    ].join("\n"), {
+      ].join("\n"),
+      {
         sourceMap: true,
-    });
+      },
+    );
 
-    assert.deepEqual([
+    assert.deepEqual(
+      [
         "function _classCallCheck(instance, Constructor) {",
         "  if (!(instance instanceof Constructor)) {",
-      "    throw new TypeError(\"Cannot call a class as a function\");",
+        '    throw new TypeError("Cannot call a class as a function");',
         "  }",
         "}",
         "",
         "let Foo = function Foo() {",
         "  _classCallCheck(this, Foo);",
         "};",
-    ].join("\n"), result.code);
+      ].join("\n"),
+      result.code,
+    );
 
     const consumer = new sourceMap.SourceMapConsumer(result.map);
 
-    assert.deepEqual(consumer.originalPositionFor({
+    assert.deepEqual(
+      consumer.originalPositionFor({
         line: 7,
         column: 4,
-    }), {
+      }),
+      {
         name: null,
         source: "stdout",
         line: 1,
         column: 6,
-    });
+      },
+    );
   });
 
-  it("code option false", function () {
+  it("code option false", function() {
-    return transformAsync("foo('bar');", { code: false }).then(function (result) {
+    return transformAsync("foo('bar');", { code: false }).then(function(
+      result,
+    ) {
       assert.ok(!result.code);
     });
   });
 
-  it("ast option false", function () {
+  it("ast option false", function() {
-    return transformAsync("foo('bar');", { ast: false }).then(function (result) {
+    return transformAsync("foo('bar');", { ast: false }).then(function(result) {
       assert.ok(!result.ast);
     });
   });
 
-  it("auxiliaryComment option", function () {
+  it("auxiliaryComment option", function() {
     return transformAsync("class Foo {}", {
       auxiliaryCommentBefore: "before",
       auxiliaryCommentAfter: "after",
-      plugins: [function (babel) {
+      plugins: [
+        function(babel) {
           const t = babel.types;
           return {
             visitor: {
-            Program: function (path) {
+              Program: function(path) {
-              path.unshiftContainer("body", t.expressionStatement(t.identifier("start")));
+                path.unshiftContainer(
-              path.pushContainer("body", t.expressionStatement(t.identifier("end")));
+                  "body",
+                  t.expressionStatement(t.identifier("start")),
+                );
+                path.pushContainer(
+                  "body",
+                  t.expressionStatement(t.identifier("end")),
+                );
               },
             },
           };
-      }],
+        },
-    }).then(function (result) {
+      ],
-      assert.equal(result.code,
+    }).then(function(result) {
-        "/*before*/start;\n/*after*/class Foo {}\n/*before*/end;\n/*after*/");
+      assert.equal(
+        result.code,
+        "/*before*/start;\n/*after*/class Foo {}\n/*before*/end;\n/*after*/",
+      );
     });
   });
 
-  it("modules metadata", function () {
+  it("modules metadata", function() {
     return Promise.all([
       // eslint-disable-next-line max-len
-      transformAsync("import { externalName as localName } from \"external\";").then(function (result) {
+      transformAsync(
+        'import { externalName as localName } from "external";',
+      ).then(function(result) {
         assert.deepEqual(result.metadata.modules.imports[0], {
           source: "external",
           imported: ["externalName"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "named",
               imported: "externalName",
               local: "localName",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("import * as localName2 from \"external\";").then(function (result) {
+      transformAsync('import * as localName2 from "external";').then(function(
+        result,
+      ) {
         assert.deepEqual(result.metadata.modules.imports[0], {
           source: "external",
           imported: ["*"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "namespace",
               local: "localName2",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("import localName3 from \"external\";").then(function (result) {
+      transformAsync('import localName3 from "external";').then(function(
+        result,
+      ) {
         assert.deepEqual(result.metadata.modules.imports[0], {
           source: "external",
           imported: ["default"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "named",
               imported: "default",
               local: "localName3",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("import localName from \"./array\";", {
+      transformAsync('import localName from "./array";', {
         resolveModuleSource: function() {
           return "override-source";
         },
-      }).then(function (result) {
+      }).then(function(result) {
         assert.deepEqual(result.metadata.modules.imports, [
           {
             source: "override-source",
             imported: ["default"],
             specifiers: [
               {
-                "kind": "named",
+                kind: "named",
-                "imported": "default",
+                imported: "default",
-                "local": "localName",
+                local: "localName",
               },
             ],
           },
         ]);
       }),
 
-      transformAsync("export * as externalName1 from \"external\";", {
+      transformAsync('export * as externalName1 from "external";', {
         plugins: [require("../../babel-plugin-syntax-export-extensions")],
-      }).then(function (result) {
+      }).then(function(result) {
         assert.deepEqual(result.metadata.modules.exports, {
           exported: ["externalName1"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "external-namespace",
               exported: "externalName1",
               source: "external",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("export externalName2 from \"external\";", {
+      transformAsync('export externalName2 from "external";', {
         plugins: [require("../../babel-plugin-syntax-export-extensions")],
-      }).then(function (result) {
+      }).then(function(result) {
         assert.deepEqual(result.metadata.modules.exports, {
           exported: ["externalName2"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "external",
               local: "externalName2",
               exported: "externalName2",
               source: "external",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("export function namedFunction() {}").then(function (result) {
+      transformAsync("export function namedFunction() {}").then(function(
+        result,
+      ) {
         assert.deepEqual(result.metadata.modules.exports, {
           exported: ["namedFunction"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "local",
               local: "namedFunction",
               exported: "namedFunction",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("export var foo = \"bar\";").then(function (result) {
+      transformAsync('export var foo = "bar";').then(function(result) {
         assert.deepEqual(result.metadata.modules.exports, {
-          "exported": ["foo"],
+          exported: ["foo"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "local",
               local: "foo",
               exported: "foo",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("export { localName as externalName3 };").then(function (result) {
+      transformAsync("export { localName as externalName3 };").then(function(
+        result,
+      ) {
         assert.deepEqual(result.metadata.modules.exports, {
           exported: ["externalName3"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "local",
               local: "localName",
               exported: "externalName3",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("export { externalName4 } from \"external\";").then(function (result) {
+      transformAsync('export { externalName4 } from "external";').then(function(
+        result,
+      ) {
         assert.deepEqual(result.metadata.modules.exports, {
           exported: ["externalName4"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "external",
               local: "externalName4",
               exported: "externalName4",
               source: "external",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("export * from \"external\";").then(function (result) {
+      transformAsync('export * from "external";').then(function(result) {
         assert.deepEqual(result.metadata.modules.exports, {
           exported: [],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "external-all",
               source: "external",
-          }],
+            },
+          ],
         });
       }),
 
-      transformAsync("export default function defaultFunction() {}").then(function (result) {
+      transformAsync(
+        "export default function defaultFunction() {}",
+      ).then(function(result) {
         assert.deepEqual(result.metadata.modules.exports, {
           exported: ["defaultFunction"],
-          specifiers: [{
+          specifiers: [
+            {
               kind: "local",
               local: "defaultFunction",
               exported: "default",
-          }],
+            },
+          ],
         });
       }),
     ]);
   });
 
-  it("ignore option", function () {
+  it("ignore option", function() {
     return Promise.all([
       transformAsync("", {
         ignore: ["/foo"],
@@ -610,7 +713,7 @@ describe("api", function () {
     ]);
   });
 
-  it("only option", function () {
+  it("only option", function() {
     return Promise.all([
       transformAsync("", {
         only: ["/foo"],
@@ -649,23 +752,23 @@ describe("api", function () {
     ]);
   });
 
-  describe("env option", function () {
+  describe("env option", function() {
     const oldBabelEnv = process.env.BABEL_ENV;
     const oldNodeEnv = process.env.NODE_ENV;
 
-    setup(function () {
+    setup(function() {
       // Tests need to run with the default and specific values for these. They
       // need to be cleared for each test.
       delete process.env.BABEL_ENV;
       delete process.env.NODE_ENV;
     });
 
-    suiteTeardown(function () {
+    suiteTeardown(function() {
       process.env.BABEL_ENV = oldBabelEnv;
       process.env.NODE_ENV = oldNodeEnv;
     });
 
-    it("default", function () {
+    it("default", function() {
       const result = babel.transform("foo;", {
         env: {
           development: { code: false },
@@ -675,7 +778,7 @@ describe("api", function () {
       assert.equal(result.code, undefined);
     });
 
-    it("BABEL_ENV", function () {
+    it("BABEL_ENV", function() {
       process.env.BABEL_ENV = "foo";
       const result = babel.transform("foo;", {
         env: {
@@ -685,7 +788,7 @@ describe("api", function () {
       assert.equal(result.code, undefined);
     });
 
-    it("NODE_ENV", function () {
+    it("NODE_ENV", function() {
       process.env.NODE_ENV = "foo";
       const result = babel.transform("foo;", {
         env: {
@@ -696,41 +799,43 @@ describe("api", function () {
     });
   });
 
-  it("resolveModuleSource option", function () {
+  it("resolveModuleSource option", function() {
     /* eslint-disable max-len */
-    const actual = "import foo from \"foo-import-default\";\nimport \"foo-import-bare\";\nexport { foo } from \"foo-export-named\";";
+    const actual =
-    const expected = "import foo from \"resolved/foo-import-default\";\nimport \"resolved/foo-import-bare\";\nexport { foo } from \"resolved/foo-export-named\";";
+      'import foo from "foo-import-default";\nimport "foo-import-bare";\nexport { foo } from "foo-export-named";';
+    const expected =
+      'import foo from "resolved/foo-import-default";\nimport "resolved/foo-import-bare";\nexport { foo } from "resolved/foo-export-named";';
     /* eslint-enable max-len */
 
     return transformAsync(actual, {
-      resolveModuleSource: function (originalSource) {
+      resolveModuleSource: function(originalSource) {
         return "resolved/" + originalSource;
       },
-    }).then(function (result) {
+    }).then(function(result) {
       assert.equal(result.code.trim(), expected);
     });
   });
 
-  describe("buildExternalHelpers", function () {
+  describe("buildExternalHelpers", function() {
-    it("all", function () {
+    it("all", function() {
       const script = buildExternalHelpers();
       assert.ok(script.indexOf("classCallCheck") >= -1);
       assert.ok(script.indexOf("inherits") >= 0);
     });
 
-    it("whitelist", function () {
+    it("whitelist", function() {
       const script = buildExternalHelpers(["inherits"]);
       assert.ok(script.indexOf("classCallCheck") === -1);
       assert.ok(script.indexOf("inherits") >= 0);
     });
 
-    it("empty whitelist", function () {
+    it("empty whitelist", function() {
       const script = buildExternalHelpers([]);
       assert.ok(script.indexOf("classCallCheck") === -1);
       assert.ok(script.indexOf("inherits") === -1);
     });
 
-    it("underscored", function () {
+    it("underscored", function() {
       const script = buildExternalHelpers(["typeof"]);
       assert.ok(script.indexOf("typeof") >= 0);
     });

packages/babel-core/test/browserify.js

@@ -5,7 +5,9 @@ import vm from "vm";
 
 describe("browserify", function() {
   it("babel/register may be used without breaking browserify", function(done) {
-    const bundler = browserify(path.join(__dirname, "fixtures/browserify/register.js"));
+    const bundler = browserify(
+      path.join(__dirname, "fixtures/browserify/register.js"),
+    );
 
     bundler.bundle(function(err, bundle) {
       if (err) return done(err);

packages/babel-core/test/caching-api.js

@@ -27,7 +27,6 @@ describe("caching API", () => {
       return { arg, count: count++ };
     });
 
-
     assert.deepEqual(fn("one"), { arg: "one", count: 0 });
     assert.equal(fn("one"), fn("one"));
 
@@ -210,48 +209,97 @@ describe("caching API", () => {
       return { arg, val, val2, count: count++ };
     });
 
-    assert.deepEqual(fn("one"), { arg: "one", val: "default", val2: "another", count: 0 });
+    assert.deepEqual(fn("one"), {
+      arg: "one",
+      val: "default",
+      val2: "another",
+      count: 0,
+    });
     assert.equal(fn("one"), fn("one"));
 
-    assert.deepEqual(fn("two"), { arg: "two", val: "default", val2: "another", count: 1 });
+    assert.deepEqual(fn("two"), {
+      arg: "two",
+      val: "default",
+      val2: "another",
+      count: 1,
+    });
     assert.equal(fn("two"), fn("two"));
 
     other = "new";
 
-    assert.deepEqual(fn("one"), { arg: "one", val: "new", val2: "another", count: 2 });
+    assert.deepEqual(fn("one"), {
+      arg: "one",
+      val: "new",
+      val2: "another",
+      count: 2,
+    });
     assert.equal(fn("one"), fn("one"));
 
-    assert.deepEqual(fn("two"), { arg: "two", val: "new", val2: "another", count: 3 });
+    assert.deepEqual(fn("two"), {
+      arg: "two",
+      val: "new",
+      val2: "another",
+      count: 3,
+    });
     assert.equal(fn("two"), fn("two"));
 
     other = "default";
 
-    assert.deepEqual(fn("one"), { arg: "one", val: "default", val2: "another", count: 4 });
+    assert.deepEqual(fn("one"), {
+      arg: "one",
+      val: "default",
+      val2: "another",
+      count: 4,
+    });
     assert.equal(fn("one"), fn("one"));
 
-    assert.deepEqual(fn("two"), { arg: "two", val: "default", val2: "another", count: 5 });
+    assert.deepEqual(fn("two"), {
+      arg: "two",
+      val: "default",
+      val2: "another",
+      count: 5,
+    });
     assert.equal(fn("two"), fn("two"));
 
     other = "new";
 
-    assert.deepEqual(fn("one"), { arg: "one", val: "new", val2: "another", count: 6 });
+    assert.deepEqual(fn("one"), {
+      arg: "one",
+      val: "new",
+      val2: "another",
+      count: 6,
+    });
     assert.equal(fn("one"), fn("one"));
 
-    assert.deepEqual(fn("two"), { arg: "two", val: "new", val2: "another", count: 7 });
+    assert.deepEqual(fn("two"), {
+      arg: "two",
+      val: "new",
+      val2: "another",
+      count: 7,
+    });
     assert.equal(fn("two"), fn("two"));
 
     another = "second";
 
-    assert.deepEqual(fn("one"), { arg: "one", val: "new", val2: "second", count: 8 });
+    assert.deepEqual(fn("one"), {
+      arg: "one",
+      val: "new",
+      val2: "second",
+      count: 8,
+    });
     assert.equal(fn("one"), fn("one"));
 
-    assert.deepEqual(fn("two"), { arg: "two", val: "new", val2: "second", count: 9 });
+    assert.deepEqual(fn("two"), {
+      arg: "two",
+      val: "new",
+      val2: "second",
+      count: 9,
+    });
     assert.equal(fn("two"), fn("two"));
-
   });
 
   it("should throw if caching is never configured and not defaulting", () => {
-    const fn = makeStrongCache(() => { }, false /* autoPermacache */);
+    const fn = makeStrongCache(() => {}, false /* autoPermacache */);
 
     assert.throws(() => fn(), /Error: Caching was left unconfigured./);
   });
@@ -259,7 +307,7 @@ describe("caching API", () => {
   it("should auto-permacache by default", () => {
     let count = 0;
 
-    const fn = makeStrongCache((arg) => ({ arg, count: count++ }));
+    const fn = makeStrongCache(arg => ({ arg, count: count++ }));
 
     assert.deepEqual(fn("one"), { arg: "one", count: 0 });
     assert.equal(fn("one"), fn("one"));
@@ -333,7 +381,10 @@ describe("caching API", () => {
   it("should throw if you configure .forever after exiting", () => {
     const fn = makeStrongCache((arg, cache) => cache);
 
-    assert.throws(() => fn().forever(), /Cannot change caching after evaluation/);
+    assert.throws(
+      () => fn().forever(),
+      /Cannot change caching after evaluation/,
+    );
   });
 
   it("should throw if you configure .never after exiting", () => {
@@ -345,12 +396,18 @@ describe("caching API", () => {
   it("should throw if you configure .using after exiting", () => {
     const fn = makeStrongCache((arg, cache) => cache);
 
-    assert.throws(() => fn().using(() => null), /Cannot change caching after evaluation/);
+    assert.throws(
+      () => fn().using(() => null),
+      /Cannot change caching after evaluation/,
+    );
   });
 
   it("should throw if you configure .invalidate after exiting", () => {
     const fn = makeStrongCache((arg, cache) => cache);
 
-    assert.throws(() => fn().invalidate(() => null), /Cannot change caching after evaluation/);
+    assert.throws(
+      () => fn().invalidate(() => null),
+      /Cannot change caching after evaluation/,
+    );
   });
 });

packages/babel-core/test/config-chain.js

@@ -4,7 +4,7 @@ import buildConfigChain from "../lib/config/build-config-chain";
 
 function fixture() {
   const args = [__dirname, "fixtures", "config"];
-  for (let i = 0; i < arguments.length; i ++) {
+  for (let i = 0; i < arguments.length; i++) {
     args.push(arguments[i]);
   }
   return path.join.apply(path, args);
@@ -14,11 +14,11 @@ function base() {
   return process.cwd();
 }
 
-describe("buildConfigChain", function () {
+describe("buildConfigChain", function() {
   let oldBabelEnv;
   let oldNodeEnv;
 
-  beforeEach(function () {
+  beforeEach(function() {
     oldBabelEnv = process.env.BABEL_ENV;
     oldNodeEnv = process.env.NODE_ENV;
 
@@ -26,7 +26,7 @@ describe("buildConfigChain", function () {
     delete process.env.NODE_ENV;
   });
 
-  afterEach(function () {
+  afterEach(function() {
     process.env.BABEL_ENV = oldBabelEnv;
     process.env.NODE_ENV = oldNodeEnv;
   });
@@ -52,7 +52,7 @@ describe("buildConfigChain", function () {
     });
   });
 
-  it("dir1", function () {
+  it("dir1", function() {
     const chain = buildConfigChain({
       filename: fixture("dir1", "src.js"),
     });
@@ -61,9 +61,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["extended"],
-            "extended",
-          ],
         },
         alias: fixture("extended.babelrc.json"),
         loc: fixture("extended.babelrc.json"),
@@ -72,9 +70,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["root"],
-            "root",
-          ],
         },
         alias: fixture(".babelrc"),
         loc: fixture(".babelrc"),
@@ -83,9 +79,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -105,7 +99,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("dir2", function () {
+  it("dir2", function() {
     const chain = buildConfigChain({
       filename: fixture("dir2", "src.js"),
     });
@@ -114,9 +108,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -125,9 +117,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["dir2"],
-            "dir2",
-          ],
         },
         alias: fixture("dir2", ".babelrc"),
         loc: fixture("dir2", ".babelrc"),
@@ -147,7 +137,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("dir3", function () {
+  it("dir3", function() {
     const chain = buildConfigChain({
       filename: fixture("dir3", "src.js"),
     });
@@ -156,9 +146,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["extended"],
-            "extended",
-          ],
         },
         alias: fixture("extended.babelrc.json"),
         loc: fixture("extended.babelrc.json"),
@@ -167,9 +155,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["root"],
-            "root",
-          ],
         },
         alias: fixture(".babelrc"),
         loc: fixture(".babelrc"),
@@ -178,9 +164,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -200,7 +184,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("env - base", function () {
+  it("env - base", function() {
     const chain = buildConfigChain({
       filename: fixture("env", "src.js"),
     });
@@ -209,9 +193,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -220,9 +202,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["env-base"],
-            "env-base",
-          ],
         },
         alias: fixture("env", ".babelrc"),
         loc: fixture("env", ".babelrc"),
@@ -242,7 +222,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("env - foo", function () {
+  it("env - foo", function() {
     process.env.NODE_ENV = "foo";
 
     const chain = buildConfigChain({
@@ -253,9 +233,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -264,9 +242,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["env-base"],
-            "env-base",
-          ],
         },
         alias: fixture("env", ".babelrc"),
         loc: fixture("env", ".babelrc"),
@@ -275,9 +251,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["env-foo"],
-            "env-foo",
-          ],
         },
         alias: fixture("env", ".babelrc.env.foo"),
         loc: fixture("env", ".babelrc.env.foo"),
@@ -297,7 +271,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("env - bar", function () {
+  it("env - bar", function() {
     process.env.NODE_ENV = "foo"; // overridden
     process.env.NODE_ENV = "bar";
 
@@ -309,9 +283,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -320,9 +292,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["env-base"],
-            "env-base",
-          ],
         },
         alias: fixture("env", ".babelrc"),
         loc: fixture("env", ".babelrc"),
@@ -331,9 +301,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["env-bar"],
-            "env-bar",
-          ],
         },
         alias: fixture("env", ".babelrc.env.bar"),
         loc: fixture("env", ".babelrc.env.bar"),
@@ -353,8 +321,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-
+  it("env - foo", function() {
-  it("env - foo", function () {
     process.env.NODE_ENV = "foo";
 
     const chain = buildConfigChain({
@@ -394,7 +361,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("js-config", function () {
+  it("js-config", function() {
     const chain = buildConfigChain({
       filename: fixture("js-config", "src.js"),
     });
@@ -403,9 +370,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -414,10 +379,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["foo", "bar"],
-            "foo",
-            "bar",
-          ],
         },
         alias: fixture("js-config", ".babelrc.js"),
         loc: fixture("js-config", ".babelrc.js"),
@@ -437,7 +399,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("js-config-function", function () {
+  it("js-config-function", function() {
     const chain = buildConfigChain({
       filename: fixture("js-config-function", "src.js"),
     });
@@ -446,9 +408,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -477,7 +437,7 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("js-config-default - should read transpiled export default", function () {
+  it("js-config-default - should read transpiled export default", function() {
     const chain = buildConfigChain({
       filename: fixture("js-config-default", "src.js"),
     });
@@ -486,9 +446,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -497,10 +455,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["foo", "bar"],
-            "foo",
-            "bar",
-          ],
         },
         alias: fixture("js-config-default", ".babelrc.js"),
         loc: fixture("js-config-default", ".babelrc.js"),
@@ -519,7 +474,7 @@ describe("buildConfigChain", function () {
 
     assert.deepEqual(chain, expected);
   });
-  it("js-config-extended", function () {
+  it("js-config-extended", function() {
     const chain = buildConfigChain({
       filename: fixture("js-config-extended", "src.js"),
     });
@@ -528,9 +483,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -539,9 +492,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["extended"],
-            "extended",
-          ],
         },
         alias: fixture("extended.babelrc.json"),
         loc: fixture("extended.babelrc.json"),
@@ -550,10 +501,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          plugins: [
+          plugins: ["foo", "bar"],
-            "foo",
-            "bar",
-          ],
         },
         alias: fixture("js-config-extended", ".babelrc.js"),
         loc: fixture("js-config-extended", ".babelrc.js"),
@@ -573,8 +521,10 @@ describe("buildConfigChain", function () {
     assert.deepEqual(chain, expected);
   });
 
-  it("json-pkg-config-no-babel - should not throw if" +
+  it(
-    " package.json doesn't contain a `babel` field", function () {
+    "json-pkg-config-no-babel - should not throw if" +
+      " package.json doesn't contain a `babel` field",
+    function() {
       const chain = buildConfigChain({
         filename: fixture("json-pkg-config-no-babel", "src.js"),
       });
@@ -583,9 +533,7 @@ describe("buildConfigChain", function () {
         {
           type: "options",
           options: {
-          ignore: [
+            ignore: ["root-ignore"],
-            "root-ignore",
-          ],
           },
           alias: fixture(".babelignore"),
           loc: fixture(".babelignore"),
@@ -594,9 +542,7 @@ describe("buildConfigChain", function () {
         {
           type: "options",
           options: {
-          plugins: [
+            plugins: ["json"],
-            "json",
-          ],
           },
           alias: fixture("json-pkg-config-no-babel", ".babelrc"),
           loc: fixture("json-pkg-config-no-babel", ".babelrc"),
@@ -614,9 +560,10 @@ describe("buildConfigChain", function () {
       ];
 
       assert.deepEqual(chain, expected);
-  });
+    },
+  );
 
-  it("should not ignore file matching negated file pattern", function () {
+  it("should not ignore file matching negated file pattern", function() {
     const chain = buildConfigChain({
       filename: fixture("ignore-negate", "src.js"),
     });
@@ -625,9 +572,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -636,10 +581,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["*", "!src.js"],
-            "*",
-            "!src.js",
-          ],
         },
         alias: fixture("ignore-negate", ".babelrc"),
         loc: fixture("ignore-negate", ".babelrc"),
@@ -665,7 +607,7 @@ describe("buildConfigChain", function () {
     assert.equal(chain2, null);
   });
 
-  it("should not ignore file matching negated folder pattern", function () {
+  it("should not ignore file matching negated folder pattern", function() {
     const chain = buildConfigChain({
       filename: fixture("ignore-negate-folder", "folder", "src.js"),
     });
@@ -674,9 +616,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["root-ignore"],
-            "root-ignore",
-          ],
         },
         alias: fixture(".babelignore"),
         loc: fixture(".babelignore"),
@@ -685,10 +625,7 @@ describe("buildConfigChain", function () {
       {
         type: "options",
         options: {
-          ignore: [
+          ignore: ["*", "!folder"],
-            "*",
-            "!folder",
-          ],
         },
         alias: fixture("ignore-negate-folder", ".babelrc"),
         loc: fixture("ignore-negate-folder", ".babelrc"),
@@ -714,83 +651,71 @@ describe("buildConfigChain", function () {
     assert.equal(chain2, null);
   });
 
-  it("js-json-config - should throw an error if both a .babelrc" +
+  it(
-    " and a .babelrc.js are present", function () {
+    "js-json-config - should throw an error if both a .babelrc" +
-    assert.throws(
+      " and a .babelrc.js are present",
-      function () {
+    function() {
+      assert.throws(function() {
         buildConfigChain({
           filename: fixture("js-json-config", "src.js"),
         });
+      }, /Multiple configuration files found\.(.|\n)*\.babelrc(.|\n)*\.babelrc\.js/);
     },
-      /Multiple configuration files found\.(.|\n)*\.babelrc(.|\n)*\.babelrc\.js/
   );
-  });
 
-  it("js-pkg-config - should throw an error if both a .babelrc.js" +
+  it(
-    " and a package.json with a babel field are present", function () {
+    "js-pkg-config - should throw an error if both a .babelrc.js" +
-    assert.throws(
+      " and a package.json with a babel field are present",
-      function () {
+    function() {
+      assert.throws(function() {
         buildConfigChain({
           filename: fixture("js-pkg-config", "src.js"),
         });
+      }, /Multiple configuration files found\.(.|\n)*\.babelrc\.js(.|\n)*package\.json/);
     },
-      /Multiple configuration files found\.(.|\n)*\.babelrc\.js(.|\n)*package\.json/
   );
-  });
 
-  it("json-pkg-config - should throw an error if both a .babelrc" +
+  it(
-    " and a package.json with a babel field are present", function () {
+    "json-pkg-config - should throw an error if both a .babelrc" +
-    assert.throws(
+      " and a package.json with a babel field are present",
-      function () {
+    function() {
+      assert.throws(function() {
         buildConfigChain({
           filename: fixture("json-pkg-config", "src.js"),
         });
+      }, /Multiple configuration files found\.(.|\n)*\.babelrc(.|\n)*package\.json/);
     },
-      /Multiple configuration files found\.(.|\n)*\.babelrc(.|\n)*package\.json/
   );
-  });
 
-  it("js-config-error", function () {
+  it("js-config-error", function() {
-    assert.throws(
+    assert.throws(function() {
-      function () {
       buildConfigChain({
         filename: fixture("js-config-error", "src.js"),
       });
-      },
+    }, /Error while loading config/);
-      /Error while loading config/
-    );
   });
 
-  it("js-config-error2", function () {
+  it("js-config-error2", function() {
-    assert.throws(
+    assert.throws(function() {
-      function () {
       buildConfigChain({
         filename: fixture("js-config-error2", "src.js"),
       });
-      },
+    }, /Configuration should be an exported JavaScript object/);
-      /Configuration should be an exported JavaScript object/
-    );
   });
 
-  it("js-config-error3", function () {
+  it("js-config-error3", function() {
-    assert.throws(
+    assert.throws(function() {
-      function () {
       buildConfigChain({
         filename: fixture("js-config-error3", "src.js"),
       });
-      },
+    }, /Configuration should be an exported JavaScript object/);
-      /Configuration should be an exported JavaScript object/
-    );
   });
 
-  it("json-config-error", function () {
+  it("json-config-error", function() {
-    assert.throws(
+    assert.throws(function() {
-      function () {
       buildConfigChain({
         filename: fixture("json-config-error", "src.js"),
       });
-      },
+    }, /Error while parsing config/);
-      /Error while parsing config/
-    );
   });
 });

packages/babel-core/test/evaluation.js

@@ -2,20 +2,23 @@ import traverse from "babel-traverse";
 import assert from "assert";
 import { parse } from "babylon";
 
-describe("evaluation", function () {
+describe("evaluation", function() {
   function addTest(code, type, value, notConfident) {
-    it(type + ": " + code, function () {
+    it(type + ": " + code, function() {
       const visitor = {};
 
-      visitor[type] = function (path) {
+      visitor[type] = function(path) {
         const evaluate = path.evaluate();
         assert.equal(evaluate.confident, !notConfident);
         assert.deepEqual(evaluate.value, value);
       };
 
-      traverse(parse(code, {
+      traverse(
+        parse(code, {
           plugins: ["*"],
-      }), visitor);
+        }),
+        visitor,
+      );
     });
   }
 
@@ -56,14 +59,39 @@ describe("evaluation", function () {
   addTest("'abc' === 'xyz' || 1 === 1", "LogicalExpression", true);
   addTest("'abc' === 'xyz' || 1 === 10", "LogicalExpression", false);
   addTest("'abc' === 'abc' || config.flag === 1", "LogicalExpression", true);
-  addTest("obj.a === 'abc' || config.flag === 1", "LogicalExpression", undefined, true);
+  addTest(
+    "obj.a === 'abc' || config.flag === 1",
+    "LogicalExpression",
+    undefined,
+    true,
+  );
   addTest("'abc' !== 'abc' && config.flag === 1", "LogicalExpression", false);
   addTest("obj.a === 'abc' && 1 === 1", "LogicalExpression", undefined, true);
-  addTest("'abc' === 'abc' && (1 === 1 || config.flag)", "LogicalExpression", true);
+  addTest(
-  addTest("'abc' === 'xyz' || (1 === 1 && config.flag)", "LogicalExpression", undefined, true);
+    "'abc' === 'abc' && (1 === 1 || config.flag)",
-  addTest("'abc' === 'xyz' || (1 === 1 && 'four' === 'four')", "LogicalExpression", true);
+    "LogicalExpression",
-  addTest("'abc' === 'abc' && (1 === 1 && 'four' === 'four')", "LogicalExpression", true);
+    true,
+  );
+  addTest(
+    "'abc' === 'xyz' || (1 === 1 && config.flag)",
+    "LogicalExpression",
+    undefined,
+    true,
+  );
+  addTest(
+    "'abc' === 'xyz' || (1 === 1 && 'four' === 'four')",
+    "LogicalExpression",
+    true,
+  );
+  addTest(
+    "'abc' === 'abc' && (1 === 1 && 'four' === 'four')",
+    "LogicalExpression",
+    true,
+  );
   addTest("({})", "ObjectExpression", {});
   addTest("({a: '1'})", "ObjectExpression", { a: "1" });
-  addTest("({['a' + 'b']: 10 * 20, 'z': [1, 2, 3]})", "ObjectExpression", { ab: 200, z: [1, 2, 3] });
+  addTest("({['a' + 'b']: 10 * 20, 'z': [1, 2, 3]})", "ObjectExpression", {
+    ab: 200,
+    z: [1, 2, 3],
+  });
 });

packages/babel-core/test/option-manager.js

@@ -6,55 +6,51 @@ describe("option-manager", () => {
   it("throws for babel 5 plugin", () => {
     return assert.throws(() => {
       manageOptions({
-        plugins: [
+        plugins: [({ Plugin }) => new Plugin("object-assign", {})],
-          ({ Plugin }) => new Plugin("object-assign", {}),
-        ],
       });
     }, /Babel 5 plugin is being run with Babel 6/);
   });
 
   describe("mergeOptions", () => {
     it("throws for removed babel 5 options", () => {
-      return assert.throws(
+      return assert.throws(() => {
-        () => {
         manageOptions({
-            "randomOption": true,
+          randomOption: true,
         });
-        },
+      }, /Unknown option: base.randomOption/);
-        /Unknown option: base.randomOption/
-      );
     });
 
     it("throws for removed babel 5 options", () => {
       return assert.throws(
         () => {
           manageOptions({
-            "auxiliaryComment": true,
+            auxiliaryComment: true,
-            "blacklist": true,
+            blacklist: true,
           });
         },
         // eslint-disable-next-line max-len
-        /Using removed Babel 5 option: base.auxiliaryComment - Use `auxiliaryCommentBefore` or `auxiliaryCommentAfter`/
+        /Using removed Babel 5 option: base.auxiliaryComment - Use `auxiliaryCommentBefore` or `auxiliaryCommentAfter`/,
       );
     });
 
     it("throws for resolved but erroring preset", () => {
-      return assert.throws(
+      return assert.throws(() => {
-        () => {
         manageOptions({
-            "presets": [path.join(__dirname, "fixtures/option-manager/not-a-preset")],
+          presets: [
+            path.join(__dirname, "fixtures/option-manager/not-a-preset"),
+          ],
         });
-        },
+      }, /While processing: .*option-manager(?:\/|\\\\)not-a-preset\.js/);
-        /While processing: .*option-manager(?:\/|\\\\)not-a-preset\.js/
-      );
     });
   });
 
-  describe("presets", function () {
+  describe("presets", function() {
     function presetTest(name) {
-      it(name, function () {
+      it(name, function() {
         const { options, passes } = manageOptions({
-          "presets": [path.join(__dirname, "fixtures/option-manager/presets", name)],
+          presets: [
+            path.join(__dirname, "fixtures/option-manager/presets", name),
+          ],
         });
 
         assert.equal(true, Array.isArray(options.plugins));
@@ -65,10 +61,16 @@ describe("option-manager", () => {
     }
 
     function presetThrowsTest(name, msg) {
-      it(name, function () {
+      it(name, function() {
-        assert.throws(() => manageOptions({
+        assert.throws(
-          "presets": [path.join(__dirname, "fixtures/option-manager/presets", name)],
+          () =>
-        }), msg);
+            manageOptions({
+              presets: [
+                path.join(__dirname, "fixtures/option-manager/presets", name),
+              ],
+            }),
+          msg,
+        );
       });
     }
 
@@ -77,7 +79,10 @@ describe("option-manager", () => {
     presetTest("es2015_default_function");
     presetTest("es2015_default_object");
 
-    presetThrowsTest("es2015_named", /Must export a default export when using ES6 modules/);
+    presetThrowsTest(
+      "es2015_named",
+      /Must export a default export when using ES6 modules/,
+    );
     presetThrowsTest("es2015_invalid", /Unsupported format: string/);
     presetThrowsTest("es5_invalid", /Unsupported format: string/);
   });

packages/babel-core/test/path.js

@@ -2,152 +2,172 @@ import { transform } from "../lib/index";
 import Plugin from "../lib/config/plugin";
 import chai from "chai";
 
-describe("traversal path", function () {
+describe("traversal path", function() {
-  it("replaceWithSourceString", function () {
+  it("replaceWithSourceString", function() {
     const expectCode = "function foo() {}";
 
     const actualCode = transform(expectCode, {
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           visitor: {
-          FunctionDeclaration: function (path) {
+            FunctionDeclaration: function(path) {
               path.replaceWithSourceString("console.whatever()");
             },
           },
-      })],
+        }),
+      ],
     }).code;
 
     chai.expect(actualCode).to.be.equal("console.whatever();");
   });
 
-  it("replaceWith (arrow expression body to block statement body)", function () {
+  it("replaceWith (arrow expression body to block statement body)", function() {
     const expectCode = "var fn = () => true;";
 
     const actualCode = transform(expectCode, {
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           visitor: {
-          ArrowFunctionExpression: function (path) {
+            ArrowFunctionExpression: function(path) {
               path.get("body").replaceWith({
                 type: "BlockStatement",
-              body: [{
+                body: [
+                  {
                     type: "ReturnStatement",
                     argument: {
                       type: "BooleanLiteral",
                       value: true,
                     },
-              }],
+                  },
+                ],
               });
             },
           },
-      })],
+        }),
+      ],
     }).code;
 
     chai.expect(actualCode).to.be.equal("var fn = () => {\n  return true;\n};");
   });
 
-  it("replaceWith (arrow block statement body to expression body)", function () {
+  it("replaceWith (arrow block statement body to expression body)", function() {
     const expectCode = "var fn = () => { return true; }";
 
     const actualCode = transform(expectCode, {
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           visitor: {
-          ArrowFunctionExpression: function (path) {
+            ArrowFunctionExpression: function(path) {
               path.get("body").replaceWith({
                 type: "BooleanLiteral",
                 value: true,
               });
             },
           },
-      })],
+        }),
+      ],
     }).code;
 
     chai.expect(actualCode).to.be.equal("var fn = () => true;");
   });
 
-  it("replaceWith (for-in left expression to variable declaration)", function () {
+  it("replaceWith (for-in left expression to variable declaration)", function() {
     const expectCode = "for (KEY in right);";
 
     const actualCode = transform(expectCode, {
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           visitor: {
-          ForInStatement: function (path) {
+            ForInStatement: function(path) {
               path.get("left").replaceWith({
                 type: "VariableDeclaration",
                 kind: "var",
-              declarations: [{
+                declarations: [
+                  {
                     type: "VariableDeclarator",
                     id: {
                       type: "Identifier",
                       name: "KEY",
                     },
-              }],
+                  },
+                ],
               });
             },
           },
-      })],
+        }),
+      ],
     }).code;
 
     chai.expect(actualCode).to.be.equal("for (var KEY in right);");
   });
 
-  it("replaceWith (for-in left variable declaration to expression)", function () {
+  it("replaceWith (for-in left variable declaration to expression)", function() {
     const expectCode = "for (var KEY in right);";
 
     const actualCode = transform(expectCode, {
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           visitor: {
-          ForInStatement: function (path) {
+            ForInStatement: function(path) {
               path.get("left").replaceWith({
                 type: "Identifier",
                 name: "KEY",
               });
             },
           },
-      })],
+        }),
+      ],
     }).code;
 
     chai.expect(actualCode).to.be.equal("for (KEY in right);");
   });
 
-  it("replaceWith (for-loop left expression to variable declaration)", function () {
+  it("replaceWith (for-loop left expression to variable declaration)", function() {
     const expectCode = "for (KEY;;);";
 
     const actualCode = transform(expectCode, {
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           visitor: {
-          ForStatement: function (path) {
+            ForStatement: function(path) {
               path.get("init").replaceWith({
                 type: "VariableDeclaration",
                 kind: "var",
-              declarations: [{
+                declarations: [
+                  {
                     type: "VariableDeclarator",
                     id: {
                       type: "Identifier",
                       name: "KEY",
                     },
-              }],
+                  },
+                ],
               });
             },
           },
-      })],
+        }),
+      ],
     }).code;
 
     chai.expect(actualCode).to.be.equal("for (var KEY;;);");
   });
 
-  it("replaceWith (for-loop left variable declaration to expression)", function () {
+  it("replaceWith (for-loop left variable declaration to expression)", function() {
     const expectCode = "for (var KEY;;);";
 
     const actualCode = transform(expectCode, {
-      plugins: [new Plugin({
+      plugins: [
+        new Plugin({
           visitor: {
-          ForStatement: function (path) {
+            ForStatement: function(path) {
               path.get("init").replaceWith({
                 type: "Identifier",
                 name: "KEY",
               });
             },
           },
-      })],
+        }),
+      ],
     }).code;
 
     chai.expect(actualCode).to.be.equal("for (KEY;;);");

packages/babel-core/test/resolution.js

@@ -2,7 +2,7 @@ import assert from "assert";
 import * as babel from "../lib/index";
 import path from "path";
 
-describe("addon resolution", function () {
+describe("addon resolution", function() {
   const base = path.join(__dirname, "fixtures", "resolution");
 
   beforeEach(function() {
@@ -20,9 +20,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["module:preset"],
-        "module:preset",
-      ],
     });
   });
 
@@ -32,9 +30,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["module:plugin"],
-        "module:plugin",
-      ],
     });
   });
 
@@ -44,9 +40,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["mod"],
-        "mod",
-      ],
     });
   });
 
@@ -56,9 +50,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["mod"],
-        "mod",
-      ],
     });
   });
 
@@ -68,9 +60,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["babel-preset-mod"],
-        "babel-preset-mod",
-      ],
     });
   });
 
@@ -80,9 +70,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["babel-plugin-mod"],
-        "babel-plugin-mod",
-      ],
     });
   });
 
@@ -92,9 +80,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["@babel/foo"],
-        "@babel/foo",
-      ],
     });
   });
 
@@ -104,9 +90,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["@babel/foo"],
-        "@babel/foo",
-      ],
     });
   });
 
@@ -116,9 +100,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["@babel/preset-foo"],
-        "@babel/preset-foo",
-      ],
     });
   });
 
@@ -128,9 +110,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["@babel/plugin-foo"],
-        "@babel/plugin-foo",
-      ],
     });
   });
 
@@ -140,9 +120,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["@foo/mod"],
-        "@foo/mod",
-      ],
     });
   });
 
@@ -152,9 +130,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["@foo/mod"],
-        "@foo/mod",
-      ],
     });
   });
 
@@ -164,9 +140,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["@foo/babel-preset-mod"],
-        "@foo/babel-preset-mod",
-      ],
     });
   });
 
@@ -176,9 +150,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["@foo/babel-plugin-mod"],
-        "@foo/babel-plugin-mod",
-      ],
     });
   });
 
@@ -188,9 +160,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["./dir/preset.js"],
-        "./dir/preset.js",
-      ],
     });
   });
 
@@ -200,9 +170,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["./dir/plugin.js"],
-        "./dir/plugin.js",
-      ],
     });
   });
 
@@ -212,9 +180,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["mod/preset"],
-        "mod/preset",
-      ],
     });
   });
 
@@ -224,9 +190,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["mod/plugin"],
-        "mod/plugin",
-      ],
     });
   });
 
@@ -236,9 +200,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["@foo/mod/preset"],
-        "@foo/mod/preset",
-      ],
     });
   });
 
@@ -248,9 +210,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["@foo/mod/plugin"],
-        "@foo/mod/plugin",
-      ],
     });
   });
 
@@ -260,9 +220,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      presets: [
+      presets: ["@babel/mod/preset"],
-        "@babel/mod/preset",
-      ],
     });
   });
 
@@ -272,9 +230,7 @@ describe("addon resolution", function () {
     babel.transform("", {
       filename: "filename.js",
       babelrc: false,
-      plugins: [
+      plugins: ["@babel/mod/plugin"],
-        "@babel/mod/plugin",
-      ],
     });
   });
 
@@ -285,9 +241,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        presets: [
+        presets: ["foo"],
-          "foo",
-        ],
       });
       // eslint-disable-next-line max-len
     }, /Cannot find module 'babel-preset-foo'.*\n- If you want to resolve "foo", use "module:foo"/);
@@ -300,9 +254,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        plugins: [
+        plugins: ["foo"],
-          "foo",
-        ],
       });
       // eslint-disable-next-line max-len
     }, /Cannot find module 'babel-plugin-foo'.*\n- If you want to resolve "foo", use "module:foo"/);
@@ -315,9 +267,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        presets: [
+        presets: ["foo"],
-          "foo",
-        ],
       });
       // eslint-disable-next-line max-len
     }, /Cannot find module 'babel-preset-foo'.*\n- Did you mean "@babel\/foo"\?/);
@@ -330,9 +280,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        plugins: [
+        plugins: ["foo"],
-          "foo",
-        ],
       });
       // eslint-disable-next-line max-len
     }, /Cannot find module 'babel-plugin-foo'.*\n- Did you mean "@babel\/foo"\?/);
@@ -345,9 +293,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        presets: [
+        presets: ["testplugin"],
-          "testplugin",
-        ],
       });
       // eslint-disable-next-line max-len
     }, /Cannot find module 'babel-preset-testplugin'.*\n- Did you accidentally pass a preset as a plugin\?/);
@@ -360,9 +306,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        plugins: [
+        plugins: ["testpreset"],
-          "testpreset",
-        ],
       });
       // eslint-disable-next-line max-len
     }, /Cannot find module 'babel-plugin-testpreset'.*\n- Did you accidentally pass a plugin as a preset\?/);
@@ -375,9 +319,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        presets: [
+        presets: ["foo"],
-          "foo",
-        ],
       });
     }, /Cannot find module 'babel-preset-foo'/);
   });
@@ -389,9 +331,7 @@ describe("addon resolution", function () {
       babel.transform("", {
         filename: "filename.js",
         babelrc: false,
-        plugins: [
+        plugins: ["foo"],
-          "foo",
-        ],
       });
     }, /Cannot find module 'babel-plugin-foo'/);
   });

packages/babel-generator/src/buffer.js

@@ -54,7 +54,7 @@ export default class Buffer {
         configurable: true,
         enumerable: true,
         get() {
-          return this.map = map.get();
+          return (this.map = map.get());
         },
         set(value) {
           Object.defineProperty(this, "map", { value, writable: true });
@@ -81,7 +81,11 @@ export default class Buffer {
 
   queue(str: string): void {
     // Drop trailing spaces when a newline is inserted.
-    if (str === "\n") while (this._queue.length > 0 && SPACES_RE.test(this._queue[0][0])) this._queue.shift();
+    if (str === "\n") {
+      while (this._queue.length > 0 && SPACES_RE.test(this._queue[0][0])) {
+        this._queue.shift();
+      }
+    }
 
     const { line, column, filename, identifierName } = this._sourcePosition;
     this._queue.unshift([str, line, column, identifierName, filename]);
@@ -89,13 +93,26 @@ export default class Buffer {
 
   _flush(): void {
     let item;
-    while (item = this._queue.pop()) this._append(...item);
+    while ((item = this._queue.pop())) this._append(...item);
   }
 
-  _append(str: string, line: number, column: number, identifierName: ?string, filename: ?string): void {
+  _append(
+    str: string,
+    line: number,
+    column: number,
+    identifierName: ?string,
+    filename: ?string,
+  ): void {
     // If there the line is ending, adding a new mapping marker is redundant
     if (this._map && str[0] !== "\n") {
-      this._map.mark(this._position.line, this._position.column, line, column, identifierName, filename);
+      this._map.mark(
+        this._position.line,
+        this._position.column,
+        line,
+        column,
+        identifierName,
+        filename,
+      );
     }
 
     this._buf.push(str);
@@ -112,11 +129,15 @@ export default class Buffer {
   }
 
   removeTrailingNewline(): void {
-    if (this._queue.length > 0 && this._queue[0][0] === "\n") this._queue.shift();
+    if (this._queue.length > 0 && this._queue[0][0] === "\n") {
+      this._queue.shift();
+    }
   }
 
   removeLastSemicolon(): void {
-    if (this._queue.length > 0 && this._queue[0][0] === ";") this._queue.shift();
+    if (this._queue.length > 0 && this._queue[0][0] === ";") {
+      this._queue.shift();
+    }
   }
 
   endsWith(suffix: string): boolean {
@@ -133,7 +154,8 @@ export default class Buffer {
       return last === suffix;
     }
 
-    const end = this._last + this._queue.reduce((acc, item) => item[0] + acc, "");
+    const end =
+      this._last + this._queue.reduce((acc, item) => item[0] + acc, "");
     if (suffix.length <= end.length) {
       return end.slice(-suffix.length) === suffix;
     }
@@ -157,10 +179,10 @@ export default class Buffer {
 
     const pos = loc ? loc[prop] : null;
 
-    this._sourcePosition.identifierName = loc && loc.identifierName || null;
+    this._sourcePosition.identifierName = (loc && loc.identifierName) || null;
     this._sourcePosition.line = pos ? pos.line : null;
     this._sourcePosition.column = pos ? pos.column : null;
-    this._sourcePosition.filename = loc && loc.filename || null;
+    this._sourcePosition.filename = (loc && loc.filename) || null;
   }
 
   /**
@@ -190,7 +212,9 @@ export default class Buffer {
     const extra = this._queue.reduce((acc, item) => item[0] + acc, "");
     const lastIndex = extra.lastIndexOf("\n");
 
-    return lastIndex === -1 ? this._position.column + extra.length : (extra.length - 1 - lastIndex);
+    return lastIndex === -1
+      ? this._position.column + extra.length
+      : extra.length - 1 - lastIndex;
   }
 
   getCurrentLine(): number {

packages/babel-generator/src/generators/expressions.js

@@ -1,9 +1,12 @@
 import * as t from "babel-types";
 import * as n from "../node";
 
-
 export function UnaryExpression(node: Object) {
-  if (node.operator === "void" || node.operator === "delete" || node.operator === "typeof") {
+  if (
+    node.operator === "void" ||
+    node.operator === "delete" ||
+    node.operator === "typeof"
+  ) {
     this.word(node.operator);
     this.space();
   } else {
@@ -51,12 +54,16 @@ export function NewExpression(node: Object, parent: Object) {
   this.word("new");
   this.space();
   this.print(node.callee, node);
-  if (this.format.minified &&
+  if (
+    this.format.minified &&
     node.arguments.length === 0 &&
     !node.optional &&
     !t.isCallExpression(parent, { callee: node }) &&
     !t.isMemberExpression(parent) &&
-      !t.isNewExpression(parent)) return;
+    !t.isNewExpression(parent)
+  ) {
+    return;
+  }
 
   if (node.optional) {
     this.token("?.");
@@ -123,7 +130,7 @@ export function Import() {
 }
 
 function buildYieldAwait(keyword: string) {
-  return function (node: Object) {
+  return function(node: Object) {
     this.word(keyword);
 
     if (node.delegate) {
@@ -164,7 +171,9 @@ export function AssignmentPattern(node: Object) {
 export function AssignmentExpression(node: Object, parent: Object) {
   // Somewhere inside a for statement `init` node but doesn't usually
   // needs a paren except for `in` expressions: `for (a in b ? a : b;;)`
-  const parens = this.inForStatementInitCounter && node.operator === "in" &&
+  const parens =
+    this.inForStatementInitCounter &&
+    node.operator === "in" &&
     !n.needsParens(node, parent);
 
   if (parens) {

packages/babel-generator/src/generators/flow.js

@@ -159,7 +159,10 @@ export function FunctionTypeAnnotation(node: Object, parent: Object) {
   this.token(")");
 
   // this node type is overloaded, not sure why but it makes it EXTREMELY annoying
-  if (parent.type === "ObjectTypeCallProperty" || parent.type === "DeclareFunction") {
+  if (
+    parent.type === "ObjectTypeCallProperty" ||
+    parent.type === "DeclareFunction"
+  ) {
     this.token(":");
   } else {
     this.space();
@@ -183,7 +186,10 @@ export function InterfaceExtends(node: Object) {
   this.print(node.typeParameters, node);
 }
 
-export { InterfaceExtends as ClassImplements, InterfaceExtends as GenericTypeAnnotation };
+export {
+  InterfaceExtends as ClassImplements,
+  InterfaceExtends as GenericTypeAnnotation,
+};
 
 export function _interfaceish(node: Object) {
   this.print(node.id, node);

packages/babel-generator/src/generators/methods.js

@@ -4,7 +4,7 @@ export function _params(node: Object) {
   this.print(node.typeParameters, node);
   this.token("(");
   this.printList(node.params, node, {
-    iterator: (node) => {
+    iterator: node => {
       if (node.optional) this.token("?");
       this.print(node.typeAnnotation, node);
     },
@@ -79,7 +79,11 @@ export function ArrowFunctionExpression(node: Object) {
 
   const firstParam = node.params[0];
 
-  if (node.params.length === 1 && t.isIdentifier(firstParam) && !hasTypes(node, firstParam)) {
+  if (
+    node.params.length === 1 &&
+    t.isIdentifier(firstParam) &&
+    !hasTypes(node, firstParam)
+  ) {
     this.print(firstParam, node);
   } else {
     this._params(node);
@@ -93,6 +97,11 @@ export function ArrowFunctionExpression(node: Object) {
 }
 
 function hasTypes(node, param) {
-  return node.typeParameters || node.returnType || param.typeAnnotation || param.optional ||
+  return (
-    param.trailingComments;
+    node.typeParameters ||
+    node.returnType ||
+    param.typeAnnotation ||
+    param.optional ||
+    param.trailingComments
+  );
 }

packages/babel-generator/src/generators/modules.js

@@ -91,7 +91,10 @@ function ExportDeclaration(node: Object) {
     let hasSpecial = false;
     while (true) {
       const first = specifiers[0];
-      if (t.isExportDefaultSpecifier(first) || t.isExportNamespaceSpecifier(first)) {
+      if (
+        t.isExportDefaultSpecifier(first) ||
+        t.isExportNamespaceSpecifier(first)
+      ) {
         hasSpecial = true;
         this.print(specifiers.shift(), node);
         if (specifiers.length) {
@@ -138,7 +141,10 @@ export function ImportDeclaration(node: Object) {
     // print "special" specifiers first
     while (true) {
       const first = specifiers[0];
-      if (t.isImportDefaultSpecifier(first) || t.isImportNamespaceSpecifier(first)) {
+      if (
+        t.isImportDefaultSpecifier(first) ||
+        t.isImportNamespaceSpecifier(first)
+      ) {
         this.print(specifiers.shift(), node);
         if (specifiers.length) {
           this.token(",");

packages/babel-generator/src/generators/statements.js

@@ -17,7 +17,8 @@ export function IfStatement(node: Object) {
   this.token(")");
   this.space();
 
-  const needsBlock = node.alternate && t.isIfStatement(getLastStatement(node.consequent));
+  const needsBlock =
+    node.alternate && t.isIfStatement(getLastStatement(node.consequent));
   if (needsBlock) {
     this.token("{");
     this.newline();
@@ -80,8 +81,8 @@ export function WhileStatement(node: Object) {
   this.printBlock(node);
 }
 
-const buildForXStatement = function (op) {
+const buildForXStatement = function(op) {
-  return function (node: Object) {
+  return function(node: Object) {
     this.word("for");
     this.space();
     if (op === "of" && node.await) {
@@ -116,7 +117,7 @@ export function DoWhileStatement(node: Object) {
 }
 
 function buildLabelStatement(prefix, key = "label") {
-  return function (node: Object) {
+  return function(node: Object) {
     this.word(prefix);
 
     const label = node[key];
@@ -261,7 +262,10 @@ export function VariableDeclaration(node: Object, parent: Object) {
 
   let separator;
   if (hasInits) {
-    separator = node.kind === "const" ? constDeclarationIndent : variableDeclarationIndent;
+    separator =
+      node.kind === "const"
+        ? constDeclarationIndent
+        : variableDeclarationIndent;
   }
 
   //

packages/babel-generator/src/generators/types.js

@@ -10,9 +10,7 @@ export function RestElement(node: Object) {
   this.print(node.argument, node);
 }
 
-export {
+export { RestElement as SpreadElement };
-  RestElement as SpreadElement,
-};
 
 export function ObjectExpression(node: Object) {
   const props = node.properties;
@@ -45,8 +43,11 @@ export function ObjectProperty(node: Object) {
     this.token("]");
   } else {
     // print `({ foo: foo = 5 } = {})` as `({ foo = 5 } = {});`
-    if (t.isAssignmentPattern(node.value) && t.isIdentifier(node.key) &&
+    if (
-      node.key.name === node.value.left.name) {
+      t.isAssignmentPattern(node.value) &&
+      t.isIdentifier(node.key) &&
+      node.key.name === node.value.left.name
+    ) {
       this.print(node.value, node);
       return;
     }
@@ -54,10 +55,12 @@ export function ObjectProperty(node: Object) {
     this.print(node.key, node);
 
     // shorthand!
-    if (node.shorthand &&
+    if (
+      node.shorthand &&
       (t.isIdentifier(node.key) &&
         t.isIdentifier(node.value) &&
-       node.key.name === node.value.name)) {
+        node.key.name === node.value.name)
+    ) {
       return;
     }
   }

packages/babel-generator/src/index.js

@@ -61,9 +61,13 @@ function normalizeOptions(code, opts): Format {
   if (format.minified) {
     format.compact = true;
 
-    format.shouldPrintComment = format.shouldPrintComment || (() => format.comments);
+    format.shouldPrintComment =
+      format.shouldPrintComment || (() => format.comments);
   } else {
-    format.shouldPrintComment = format.shouldPrintComment || ((value) => format.comments ||
+    format.shouldPrintComment =
+      format.shouldPrintComment ||
+      (value =>
+        format.comments ||
         (value.indexOf("@license") >= 0 || value.indexOf("@preserve") >= 0));
   }
 
@@ -71,7 +75,9 @@ function normalizeOptions(code, opts): Format {
     format.compact = code.length > 500_000; // 500KB
 
     if (format.compact) {
-      console.error("[BABEL] " + messages.get("codeGeneratorDeopt", opts.filename, "500KB"));
+      console.error(
+        "[BABEL] " + messages.get("codeGeneratorDeopt", opts.filename, "500KB"),
+      );
     }
   }
 
@@ -97,7 +103,7 @@ export class CodeGenerator {
   }
 }
 
-export default function (ast: Object, opts: Object, code: string): Object {
+export default function(ast: Object, opts: Object, code: string): Object {
   const gen = new Generator(ast, opts, code);
   return gen.generate();
 }

packages/babel-generator/src/node/index.js

@@ -7,15 +7,16 @@ function expandAliases(obj) {
 
   function add(type, func) {
     const fn = newObj[type];
-    newObj[type] = fn ? function(node, parent, stack) {
+    newObj[type] = fn
+      ? function(node, parent, stack) {
           const result = fn(node, parent, stack);
 
           return result == null ? func(node, parent, stack) : result;
-    } : func;
+        }
+      : func;
   }
 
   for (const type of Object.keys(obj)) {
-
     const aliases = t.FLIPPED_ALIAS_KEYS[type];
     if (aliases) {
       for (const alias of aliases) {
@@ -46,8 +47,10 @@ function isOrHasCallExpression(node) {
   }
 
   if (t.isMemberExpression(node)) {
-    return isOrHasCallExpression(node.object) ||
+    return (
-      (!node.computed && isOrHasCallExpression(node.property));
+      isOrHasCallExpression(node.object) ||
+      (!node.computed && isOrHasCallExpression(node.property))
+    );
   } else {
     return false;
   }

packages/babel-generator/src/node/parentheses.js

@@ -38,11 +38,19 @@ export function UpdateExpression(node: Object, parent: Object): boolean {
   return t.isMemberExpression(parent) && parent.object === node;
 }
 
-export function ObjectExpression(node: Object, parent: Object, printStack: Array<Object>): boolean {
+export function ObjectExpression(
+  node: Object,
+  parent: Object,
+  printStack: Array<Object>,
+): boolean {
   return isFirstInStatement(printStack, { considerArrow: true });
 }
 
-export function DoExpression(node: Object, parent: Object, printStack: Array<Object>): boolean {
+export function DoExpression(
+  node: Object,
+  parent: Object,
+  printStack: Array<Object>,
+): boolean {
   return isFirstInStatement(printStack);
 }
 
@@ -55,7 +63,8 @@ export function Binary(node: Object, parent: Object): boolean {
   }
 
   if (
-    ((t.isCallExpression(parent) || t.isNewExpression(parent)) && parent.callee === node) ||
+    ((t.isCallExpression(parent) || t.isNewExpression(parent)) &&
+      parent.callee === node) ||
     t.isUnaryLike(parent) ||
     (t.isMemberExpression(parent) && parent.object === node) ||
     t.isAwaitExpression(parent)
@@ -72,7 +81,9 @@ export function Binary(node: Object, parent: Object): boolean {
 
     if (
       // Logical expressions with the same precedence don't need parens.
-      (parentPos === nodePos && parent.right === node && !t.isLogicalExpression(parent)) ||
+      (parentPos === nodePos &&
+        parent.right === node &&
+        !t.isLogicalExpression(parent)) ||
       parentPos > nodePos
     ) {
       return true;
@@ -85,11 +96,13 @@ export function Binary(node: Object, parent: Object): boolean {
 export function BinaryExpression(node: Object, parent: Object): boolean {
   // let i = (1 in []);
   // for ((1 in []);;);
-  return node.operator === "in" && (t.isVariableDeclarator(parent) || t.isFor(parent));
+  return (
+    node.operator === "in" &&
+    (t.isVariableDeclarator(parent) || t.isFor(parent))
+  );
 }
 
 export function SequenceExpression(node: Object, parent: Object): boolean {
-
   if (
     // Although parentheses wouldn"t hurt around sequence
     // expressions in the head of for loops, traditional style
@@ -113,29 +126,40 @@ export function SequenceExpression(node: Object, parent: Object): boolean {
 }
 
 export function YieldExpression(node: Object, parent: Object): boolean {
-  return t.isBinary(parent) ||
+  return (
+    t.isBinary(parent) ||
     t.isUnaryLike(parent) ||
     t.isCallExpression(parent) ||
     t.isMemberExpression(parent) ||
     t.isNewExpression(parent) ||
-         (t.isConditionalExpression(parent) && node === parent.test);
+    (t.isConditionalExpression(parent) && node === parent.test)
-
+  );
 }
 
 export { YieldExpression as AwaitExpression };
 
-export function ClassExpression(node: Object, parent: Object, printStack: Array<Object>): boolean {
+export function ClassExpression(
+  node: Object,
+  parent: Object,
+  printStack: Array<Object>,
+): boolean {
   return isFirstInStatement(printStack, { considerDefaultExports: true });
 }
 
 export function UnaryLike(node: Object, parent: Object): boolean {
-  return t.isMemberExpression(parent, { object: node }) ||
+  return (
+    t.isMemberExpression(parent, { object: node }) ||
     t.isCallExpression(parent, { callee: node }) ||
     t.isNewExpression(parent, { callee: node }) ||
-         t.isBinaryExpression(parent, { operator: "**", left: node });
+    t.isBinaryExpression(parent, { operator: "**", left: node })
+  );
 }
 
-export function FunctionExpression(node: Object, parent: Object, printStack: Array<Object>): boolean {
+export function FunctionExpression(
+  node: Object,
+  parent: Object,
+  printStack: Array<Object>,
+): boolean {
   return isFirstInStatement(printStack, { considerDefaultExports: true });
 }
 
@@ -167,10 +191,10 @@ export function AssignmentExpression(node: Object): boolean {
 
 // Walk up the print stack to deterimine if our node can come first
 // in statement.
-function isFirstInStatement(printStack: Array<Object>, {
+function isFirstInStatement(
-    considerArrow = false,
+  printStack: Array<Object>,
-    considerDefaultExports = false,
+  { considerArrow = false, considerDefaultExports = false } = {},
-  } = {}): boolean {
+): boolean {
   let i = printStack.length - 1;
   let node = printStack[i];
   i--;
@@ -179,8 +203,9 @@ function isFirstInStatement(printStack: Array<Object>, {
     if (
       t.isExpressionStatement(parent, { expression: node }) ||
       t.isTaggedTemplateExpression(parent) ||
-      considerDefaultExports && t.isExportDefaultDeclaration(parent, { declaration: node }) ||
+      (considerDefaultExports &&
-      considerArrow && t.isArrowFunctionExpression(parent, { body: node })
+        t.isExportDefaultDeclaration(parent, { declaration: node })) ||
+      (considerArrow && t.isArrowFunctionExpression(parent, { body: node }))
     ) {
       return true;
     }

packages/babel-generator/src/node/whitespace.js

@@ -3,7 +3,7 @@ import * as t from "babel-types";
 
 type WhitespaceObject = {
   before?: boolean,
-  after?: boolean
+  after?: boolean,
 };
 
 /**
@@ -45,15 +45,22 @@ function isHelper(node) {
   } else if (t.isCallExpression(node)) {
     return isHelper(node.callee);
   } else if (t.isBinary(node) || t.isAssignmentExpression(node)) {
-    return (t.isIdentifier(node.left) && isHelper(node.left)) || isHelper(node.right);
+    return (
+      (t.isIdentifier(node.left) && isHelper(node.left)) || isHelper(node.right)
+    );
   } else {
     return false;
   }
 }
 
 function isType(node) {
-  return t.isLiteral(node) || t.isObjectExpression(node) || t.isArrayExpression(node) ||
+  return (
-         t.isIdentifier(node) || t.isMemberExpression(node);
+    t.isLiteral(node) ||
+    t.isObjectExpression(node) ||
+    t.isArrayExpression(node) ||
+    t.isIdentifier(node) ||
+    t.isMemberExpression(node)
+  );
 }
 
 /**
@@ -61,7 +68,6 @@ function isType(node) {
  */
 
 export const nodes = {
-
   /**
    * Test if AssignmentExpression needs whitespace.
    */
@@ -164,9 +170,10 @@ export const nodes = {
  * Test if Property needs whitespace.
  */
 
-nodes.ObjectProperty =
+nodes.ObjectProperty = nodes.ObjectTypeProperty = nodes.ObjectMethod = function(
-nodes.ObjectTypeProperty =
+  node: Object,
-nodes.ObjectMethod = function (node: Object, parent): ?WhitespaceObject {
+  parent,
+): ?WhitespaceObject {
   if (parent.properties[0] === node) {
     return {
       before: true,
@@ -179,7 +186,6 @@ nodes.ObjectMethod = function (node: Object, parent): ?WhitespaceObject {
  */
 
 export const list = {
-
   /**
    * Return VariableDeclaration declarations init properties.
    */
@@ -216,12 +222,12 @@ export const list = {
   ["LabeledStatement", true],
   ["SwitchStatement", true],
   ["TryStatement", true],
-].forEach(function ([type, amounts]) {
+].forEach(function([type, amounts]) {
   if (typeof amounts === "boolean") {
     amounts = { after: amounts, before: amounts };
   }
-  [type].concat(t.FLIPPED_ALIAS_KEYS[type] || []).forEach(function (type) {
+  [type].concat(t.FLIPPED_ALIAS_KEYS[type] || []).forEach(function(type) {
-    nodes[type] = function () {
+    nodes[type] = function() {
       return amounts;
     };
   });

packages/babel-generator/src/printer.js

@@ -14,21 +14,21 @@ const ZERO_DECIMAL_INTEGER = /\.0+$/;
 const NON_DECIMAL_LITERAL = /^0[box]/;
 
 export type Format = {
-  shouldPrintComment: (comment: string) => boolean;
+  shouldPrintComment: (comment: string) => boolean,
-  retainLines: boolean;
+  retainLines: boolean,
-  retainFunctionParens: boolean;
+  retainFunctionParens: boolean,
-  comments: boolean;
+  comments: boolean,
-  auxiliaryCommentBefore: string;
+  auxiliaryCommentBefore: string,
-  auxiliaryCommentAfter: string;
+  auxiliaryCommentAfter: string,
-  compact: boolean | "auto";
+  compact: boolean | "auto",
-  minified: boolean;
+  minified: boolean,
-  quotes: "single" | "double";
+  quotes: "single" | "double",
-  concise: boolean;
+  concise: boolean,
   indent: {
-    adjustMultilineComment: boolean;
+    adjustMultilineComment: boolean,
-    style: string;
+    style: string,
-    base: number;
+    base: number,
-  }
+  },
 };
 
 export default class Printer {
@@ -107,7 +107,10 @@ export default class Printer {
   space(force: boolean = false): void {
     if (this.format.compact) return;
 
-    if ((this._buf.hasContent() && !this.endsWith(" ") && !this.endsWith("\n")) || force) {
+    if (
+      (this._buf.hasContent() && !this.endsWith(" ") && !this.endsWith("\n")) ||
+      force
+    ) {
       this._space();
     }
   }
@@ -149,14 +152,14 @@ export default class Printer {
   token(str: string): void {
     // space is mandatory to avoid outputting <!--
     // http://javascript.spec.whatwg.org/#comment-syntax
-    if ((str === "--" && this.endsWith("!")) ||
+    if (
-
+      (str === "--" && this.endsWith("!")) ||
       // Need spaces for operators of the same kind to avoid: `a+++b`
       (str[0] === "+" && this.endsWith("+")) ||
       (str[0] === "-" && this.endsWith("-")) ||
-
       // Needs spaces to avoid changing '34' to '34.', which would still be a valid number.
-      (str[0] === "." && this._endsWithInteger)) {
+      (str[0] === "." && this._endsWithInteger)
+    ) {
       this._space();
     }
 
@@ -294,9 +297,9 @@ export default class Printer {
    */
 
   startTerminatorless(): Object {
-    return this._parenPushNewlineState = {
+    return (this._parenPushNewlineState = {
       printed: false,
-    };
+    });
   }
 
   /**
@@ -322,7 +325,11 @@ export default class Printer {
     const printMethod = this[node.type];
     if (!printMethod) {
       // eslint-disable-next-line max-len
-      throw new ReferenceError(`unknown node of type ${JSON.stringify(node.type)} with constructor ${JSON.stringify(node && node.constructor.name)}`);
+      throw new ReferenceError(
+        `unknown node of type ${JSON.stringify(
+          node.type,
+        )} with constructor ${JSON.stringify(node && node.constructor.name)}`,
+      );
     }
 
     this._printStack.push(node);
@@ -335,7 +342,8 @@ export default class Printer {
     if (
       this.format.retainFunctionParens &&
       node.type === "FunctionExpression" &&
-      node.extra && node.extra.parenthesized
+      node.extra &&
+      node.extra.parenthesized
     ) {
       needsParens = true;
     }
@@ -343,7 +351,7 @@ export default class Printer {
 
     this._printLeadingComments(node, parent);
 
-    const loc = (t.isProgram(node) || t.isFile(node)) ? null : node.loc;
+    const loc = t.isProgram(node) || t.isFile(node) ? null : node.loc;
     this.withSource("start", loc, () => {
       this[node.type](node, parent);
     });
@@ -392,7 +400,12 @@ export default class Printer {
 
   getPossibleRaw(node) {
     const extra = node.extra;
-    if (extra && extra.raw != null && extra.rawValue != null && node.value === extra.rawValue) {
+    if (
+      extra &&
+      extra.raw != null &&
+      extra.rawValue != null &&
+      node.value === extra.rawValue
+    ) {
       return extra.raw;
     }
   }
@@ -490,14 +503,24 @@ export default class Printer {
       // user node
       if (leading) {
         const comments = node.leadingComments;
-        const comment = comments && find(comments, (comment) =>
+        const comment =
-          !!comment.loc && this.format.shouldPrintComment(comment.value));
+          comments &&
+          find(
+            comments,
+            comment =>
+              !!comment.loc && this.format.shouldPrintComment(comment.value),
+          );
 
         lines = this._whitespace.getNewlinesBefore(comment || node);
       } else {
         const comments = node.trailingComments;
-        const comment = comments && findLast(comments, (comment) =>
+        const comment =
-          !!comment.loc && this.format.shouldPrintComment(comment.value));
+          comments &&
+          findLast(
+            comments,
+            comment =>
+              !!comment.loc && this.format.shouldPrintComment(comment.value),
+          );
 
         lines = this._whitespace.getNewlinesAfter(comment || node);
       }
@@ -520,7 +543,9 @@ export default class Printer {
   _getComments(leading, node) {
     // Note, we use a boolean flag here instead of passing in the attribute name as it is faster
     // because this is called extremely frequently.
-    return (node && (leading ? node.leadingComments : node.trailingComments)) || [];
+    return (
+      (node && (leading ? node.leadingComments : node.trailingComments)) || []
+    );
   }
 
   _printComment(comment) {
@@ -539,21 +564,32 @@ export default class Printer {
     }
 
     // whitespace before
-    this.newline(this._whitespace ? this._whitespace.getNewlinesBefore(comment) : 0);
+    this.newline(
+      this._whitespace ? this._whitespace.getNewlinesBefore(comment) : 0,
+    );
 
     if (!this.endsWith("[") && !this.endsWith("{")) this.space();
 
-    let val = comment.type === "CommentLine" ? `//${comment.value}\n` : `/*${comment.value}*/`;
+    let val =
+      comment.type === "CommentLine"
+        ? `//${comment.value}\n`
+        : `/*${comment.value}*/`;
 
     //
-    if (comment.type === "CommentBlock" && this.format.indent.adjustMultilineComment) {
+    if (
+      comment.type === "CommentBlock" &&
+      this.format.indent.adjustMultilineComment
+    ) {
       const offset = comment.loc && comment.loc.start.column;
       if (offset) {
         const newlineRegex = new RegExp("\\n\\s{1," + offset + "}", "g");
         val = val.replace(newlineRegex, "\n");
       }
 
-      const indentSize = Math.max(this._getIndent().length, this._buf.getCurrentColumn());
+      const indentSize = Math.max(
+        this._getIndent().length,
+        this._buf.getCurrentColumn(),
+      );
       val = val.replace(/\n(?!$)/g, `\n${repeat(" ", indentSize)}`);
     }
 
@@ -565,9 +601,11 @@ export default class Printer {
     });
 
     // whitespace after
-    this.newline((this._whitespace ? this._whitespace.getNewlinesAfter(comment) : 0) +
+    this.newline(
+      (this._whitespace ? this._whitespace.getNewlinesAfter(comment) : 0) +
         // Subtract one to account for the line force-added above.
-      (comment.type === "CommentLine" ? -1 : 0));
+        (comment.type === "CommentLine" ? -1 : 0),
+    );
   }
 
   _printComments(comments?: Array<Object>) {

packages/babel-generator/src/source-map.js

@@ -18,16 +18,16 @@ export default class SourceMap {
 
   get() {
     if (!this._cachedMap) {
-      const map = this._cachedMap = new sourceMap.SourceMapGenerator({
+      const map = (this._cachedMap = new sourceMap.SourceMapGenerator({
         file: this._opts.sourceMapTarget,
         sourceRoot: this._opts.sourceRoot,
-      });
+      }));
 
       const code = this._code;
       if (typeof code === "string") {
         map.setSourceContent(this._opts.sourceFileName, code);
       } else if (typeof code === "object") {
-        Object.keys(code).forEach((sourceFileName) => {
+        Object.keys(code).forEach(sourceFileName => {
           map.setSourceContent(sourceFileName, code[sourceFileName]);
         });
       }
@@ -60,8 +60,11 @@ export default class SourceMap {
 
     // If this mapping points to the same source location as the last one, we can ignore it since
     // the previous one covers it.
-    if (this._lastGenLine === generatedLine && this._lastSourceLine === line &&
+    if (
-      this._lastSourceColumn === column) {
+      this._lastGenLine === generatedLine &&
+      this._lastSourceLine === line &&
+      this._lastSourceColumn === column
+    ) {
       return;
     }
 
@@ -80,7 +83,10 @@ export default class SourceMap {
         column: generatedColumn,
       },
       source: line == null ? undefined : filename || this._opts.sourceFileName,
-      original: line == null ? undefined : {
+      original:
+        line == null
+          ? undefined
+          : {
               line: line,
               column: column,
             },

packages/babel-generator/src/whitespace.js

@@ -17,7 +17,11 @@ export default class Whitespace {
     let endToken;
     const tokens = this.tokens;
 
-    let index = this._findToken((token) => token.start - node.start, 0, tokens.length);
+    let index = this._findToken(
+      token => token.start - node.start,
+      0,
+      tokens.length,
+    );
     if (index >= 0) {
       while (index && node.start === tokens[index - 1].start) --index;
       startToken = tokens[index - 1];
@@ -36,7 +40,11 @@ export default class Whitespace {
     let endToken;
     const tokens = this.tokens;
 
-    let index = this._findToken((token) => token.end - node.end, 0, tokens.length);
+    let index = this._findToken(
+      token => token.end - node.end,
+      0,
+      tokens.length,
+    );
     if (index >= 0) {
       while (index && node.end === tokens[index - 1].end) --index;
       startToken = tokens[index];

packages/babel-generator/test/index.js

@@ -9,125 +9,164 @@ import fs from "fs";
 import path from "path";
 import fixtures from "babel-helper-fixtures";
 
-describe("generation", function () {
+describe("generation", function() {
-  it("completeness", function () {
+  it("completeness", function() {
-    Object.keys(t.VISITOR_KEYS).forEach(function (type) {
+    Object.keys(t.VISITOR_KEYS).forEach(function(type) {
       assert.ok(!!Printer.prototype[type], type + " should exist");
     });
 
-    Object.keys(Printer.prototype).forEach(function (type) {
+    Object.keys(Printer.prototype).forEach(function(type) {
       if (!/[A-Z]/.test(type[0])) return;
       assert.ok(t.VISITOR_KEYS[type], type + " should not exist");
     });
   });
 
-  it("multiple sources", function () {
+  it("multiple sources", function() {
     const sources = {
       "a.js": "function hi (msg) { console.log(msg); }\n",
       "b.js": "hi('hello');\n",
     };
-    const parsed = Object.keys(sources).reduce(function (_parsed, filename) {
+    const parsed = Object.keys(sources).reduce(function(_parsed, filename) {
-      _parsed[filename] = parse(sources[filename], { sourceFilename: filename });
+      _parsed[filename] = parse(sources[filename], {
+        sourceFilename: filename,
+      });
       return _parsed;
     }, {});
 
     const combinedAst = {
-      "type": "File",
+      type: "File",
-      "program": {
+      program: {
-        "type": "Program",
+        type: "Program",
-        "sourceType": "module",
+        sourceType: "module",
-        "body": [].concat(parsed["a.js"].program.body, parsed["b.js"].program.body),
+        body: [].concat(
+          parsed["a.js"].program.body,
+          parsed["b.js"].program.body,
+        ),
       },
     };
 
     const generated = generate(combinedAst, { sourceMaps: true }, sources);
 
-    chai.expect(generated.map).to.deep.equal({
+    chai.expect(generated.map).to.deep.equal(
+      {
         version: 3,
-      sources: [ "a.js", "b.js" ],
+        sources: ["a.js", "b.js"],
-      mappings: "AAAA,SAASA,EAAT,CAAaC,GAAb,EAAkB;AAAEC,UAAQC,GAAR,CAAYF,GAAZ;AAAmB;;ACAvCD,GAAG,OAAH",
+        mappings:
-      names: [
+          "AAAA,SAASA,EAAT,CAAaC,GAAb,EAAkB;AAAEC,UAAQC,GAAR,CAAYF,GAAZ;AAAmB;;ACAvCD,GAAG,OAAH",
-        "hi",
+        names: ["hi", "msg", "console", "log"],
-        "msg",
-        "console",
-        "log",
-      ],
         sourcesContent: [
           "function hi (msg) { console.log(msg); }\n",
           "hi('hello');\n",
         ],
-    }, "sourcemap was incorrectly generated");
+      },
+      "sourcemap was incorrectly generated",
+    );
 
-    chai.expect(generated.rawMappings).to.deep.equal([
+    chai.expect(generated.rawMappings).to.deep.equal(
-      { name: undefined,
+      [
+        {
+          name: undefined,
           generated: { line: 1, column: 0 },
           source: "a.js",
-        original: { line: 1, column: 0 } },
+          original: { line: 1, column: 0 },
-      { name: "hi",
+        },
+        {
+          name: "hi",
           generated: { line: 1, column: 9 },
           source: "a.js",
-        original: { line: 1, column: 9 } },
+          original: { line: 1, column: 9 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 1, column: 11 },
           source: "a.js",
-        original: { line: 1, column: 0 } },
+          original: { line: 1, column: 0 },
-      { name: "msg",
+        },
+        {
+          name: "msg",
           generated: { line: 1, column: 12 },
           source: "a.js",
-        original: { line: 1, column: 13 } },
+          original: { line: 1, column: 13 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 1, column: 15 },
           source: "a.js",
-        original: { line: 1, column: 0 } },
+          original: { line: 1, column: 0 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 1, column: 17 },
           source: "a.js",
-        original: { line: 1, column: 18 } },
+          original: { line: 1, column: 18 },
-      { name: "console",
+        },
+        {
+          name: "console",
           generated: { line: 2, column: 0 },
           source: "a.js",
-        original: { line: 1, column: 20 } },
+          original: { line: 1, column: 20 },
-      { name: "log",
+        },
+        {
+          name: "log",
           generated: { line: 2, column: 10 },
           source: "a.js",
-        original: { line: 1, column: 28 } },
+          original: { line: 1, column: 28 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 2, column: 13 },
           source: "a.js",
-        original: { line: 1, column: 20 } },
+          original: { line: 1, column: 20 },
-      { name: "msg",
+        },
+        {
+          name: "msg",
           generated: { line: 2, column: 14 },
           source: "a.js",
-        original: { line: 1, column: 32 } },
+          original: { line: 1, column: 32 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 2, column: 17 },
           source: "a.js",
-        original: { line: 1, column: 20 } },
+          original: { line: 1, column: 20 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 3, column: 0 },
           source: "a.js",
-        original: { line: 1, column: 39 } },
+          original: { line: 1, column: 39 },
-      { name: "hi",
+        },
+        {
+          name: "hi",
           generated: { line: 5, column: 0 },
           source: "b.js",
-        original: { line: 1, column: 0 } },
+          original: { line: 1, column: 0 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 5, column: 3 },
           source: "b.js",
-        original: { line: 1, column: 3 } },
+          original: { line: 1, column: 3 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 5, column: 10 },
           source: "b.js",
-        original: { line: 1, column: 0 } },
+          original: { line: 1, column: 0 },
-    ], "raw mappings were incorrectly generated");
+        },
+      ],
+      "raw mappings were incorrectly generated",
+    );
 
-    chai.expect(generated.code).to.equal(
+    chai
+      .expect(generated.code)
+      .to.equal(
         "function hi(msg) {\n  console.log(msg);\n}\n\nhi('hello');",
-      "code was incorrectly generated"
+        "code was incorrectly generated",
       );
   });
 
-  it("identifierName", function () {
+  it("identifierName", function() {
     const code = "function foo() { bar; }\n";
 
     const ast = parse(code, { filename: "inline" }).program;
@@ -141,50 +180,74 @@ describe("generation", function () {
     id2.name += "2";
     id2.loc.identiferName = "bar";
 
-    const generated = generate(ast, {
+    const generated = generate(
+      ast,
+      {
         filename: "inline",
         sourceFileName: "inline",
         sourceMaps: true,
-    }, code);
+      },
+      code,
+    );
 
-    chai.expect(generated.map).to.deep.equal({
+    chai.expect(generated.map).to.deep.equal(
+      {
         version: 3,
         sources: ["inline"],
-      names: ["foo", "bar" ],
+        names: ["foo", "bar"],
         mappings: "AAAA,SAASA,IAAT,GAAe;AAAEC;AAAM",
-      sourcesContent: [ "function foo() { bar; }\n" ],
+        sourcesContent: ["function foo() { bar; }\n"],
-    }, "sourcemap was incorrectly generated");
+      },
+      "sourcemap was incorrectly generated",
+    );
 
-    chai.expect(generated.rawMappings).to.deep.equal([
+    chai.expect(generated.rawMappings).to.deep.equal(
-      { name: undefined,
+      [
+        {
+          name: undefined,
           generated: { line: 1, column: 0 },
           source: "inline",
-        original: { line: 1, column: 0 } },
+          original: { line: 1, column: 0 },
-      { name: "foo",
+        },
+        {
+          name: "foo",
           generated: { line: 1, column: 9 },
           source: "inline",
-        original: { line: 1, column: 9 } },
+          original: { line: 1, column: 9 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 1, column: 13 },
           source: "inline",
-        original: { line: 1, column: 0 } },
+          original: { line: 1, column: 0 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 1, column: 16 },
           source: "inline",
-        original: { line: 1, column: 15 } },
+          original: { line: 1, column: 15 },
-      { name: "bar",
+        },
+        {
+          name: "bar",
           generated: { line: 2, column: 0 },
           source: "inline",
-        original: { line: 1, column: 17 } },
+          original: { line: 1, column: 17 },
-      { name: undefined,
+        },
+        {
+          name: undefined,
           generated: { line: 3, column: 0 },
           source: "inline",
-        original: { line: 1, column: 23 } },
+          original: { line: 1, column: 23 },
-    ], "raw mappings were incorrectly generated");
+        },
+      ],
+      "raw mappings were incorrectly generated",
+    );
 
-    chai.expect(generated.code).to.equal(
+    chai
+      .expect(generated.code)
+      .to.equal(
         "function foo2() {\n  bar2;\n}",
-      "code was incorrectly generated"
+        "code was incorrectly generated",
       );
   });
 
@@ -199,17 +262,22 @@ describe("generation", function () {
 
     chai.expect(generated.rawMappings).to.be.an("array");
 
-    chai.expect(generated).ownPropertyDescriptor("map").not.to.have.property("value");
+    chai
+      .expect(generated)
+      .ownPropertyDescriptor("map")
+      .not.to.have.property("value");
 
     chai.expect(generated.map).to.be.an("object");
   });
 });
 
-
 describe("programmatic generation", function() {
   it("numeric member expression", function() {
     // Should not generate `0.foo`
-    const mem = t.memberExpression(t.numericLiteral(60702), t.identifier("foo"));
+    const mem = t.memberExpression(
+      t.numericLiteral(60702),
+      t.identifier("foo"),
+    );
     new Function(generate(mem).code);
   });
 
@@ -220,10 +288,10 @@ describe("programmatic generation", function() {
         t.stringLiteral("while cond"),
         t.ifStatement(
           t.stringLiteral("nested"),
-          t.expressionStatement(t.numericLiteral(1))
+          t.expressionStatement(t.numericLiteral(1)),
-        )
         ),
-      t.expressionStatement(t.stringLiteral("alt"))
+      ),
+      t.expressionStatement(t.stringLiteral("alt")),
     );
 
     const ast = parse(generate(ifStatement).code);
@@ -233,35 +301,22 @@ describe("programmatic generation", function() {
   it("prints directives in block with empty body", function() {
     const blockStatement = t.blockStatement(
       [],
-      [t.directive(t.directiveLiteral("use strict"))]
+      [t.directive(t.directiveLiteral("use strict"))],
     );
 
     const output = generate(blockStatement).code;
-    assert.equal(output, [
+    assert.equal(output, ["{", '  "use strict";', "}"].join("\n"));
-      "{",
-      "  \"use strict\";",
-      "}",
-    ].join("\n"));
   });
 
   it("flow object indentation", function() {
     const objectStatement = t.objectTypeAnnotation(
-      [
+      [t.objectTypeProperty(t.identifier("bar"), t.stringTypeAnnotation())],
-        t.objectTypeProperty(
+      null,
-          t.identifier("bar"),
-          t.stringTypeAnnotation()
-        ),
-      ],
       null,
-      null
     );
 
     const output = generate(objectStatement).code;
-    assert.equal(output, [
+    assert.equal(output, ["{", "  bar: string,", "}"].join("\n"));
-      "{",
-      "  bar: string,",
-      "}",
-    ].join("\n"));
   });
 
   it("flow object indentation with empty leading ObjectTypeProperty", function() {
@@ -273,21 +328,17 @@ describe("programmatic generation", function() {
           t.anyTypeAnnotation(),
           t.identifier("Test"),
         ),
-      ]
+      ],
     );
 
     const output = generate(objectStatement).code;
 
-    assert.equal(output, [
+    assert.equal(output, ["{", "  [key: any]: Test,", "}"].join("\n"));
-      "{",
-      "  [key: any]: Test,",
-      "}",
-    ].join("\n"));
   });
 });
 
-describe("whitespace", function () {
+describe("whitespace", function() {
-  it("empty token list", function () {
+  it("empty token list", function() {
     const w = new Whitespace([]);
     assert.equal(w.getNewlinesBefore(t.stringLiteral("1")), 0);
   });
@@ -295,10 +346,13 @@ describe("whitespace", function () {
 
 const suites = fixtures(`${__dirname}/fixtures`);
 
-suites.forEach(function (testSuite) {
+suites.forEach(function(testSuite) {
-  describe("generation/" + testSuite.title, function () {
+  describe("generation/" + testSuite.title, function() {
-    testSuite.tests.forEach(function (task) {
+    testSuite.tests.forEach(function(task) {
-      it(task.title, !task.disabled && function () {
+      it(
+        task.title,
+        !task.disabled &&
+          function() {
             const expect = task.expect;
             const actual = task.actual;
             const actualCode = actual.code;
@@ -326,16 +380,21 @@ suites.forEach(function (testSuite) {
               const result = generate(actualAst, task.options, actualCode);
 
               if (
-            !expect.code && result.code && fs.statSync(path.dirname(expect.loc)).isDirectory() &&
+                !expect.code &&
+                result.code &&
+                fs.statSync(path.dirname(expect.loc)).isDirectory() &&
                 !process.env.CI
               ) {
                 console.log(`New test file created: ${expect.loc}`);
                 fs.writeFileSync(expect.loc, result.code);
               } else {
-            chai.expect(result.code).to.be.equal(expect.code, actual.loc + " !== " + expect.loc);
+                chai
+                  .expect(result.code)
+                  .to.be.equal(expect.code, actual.loc + " !== " + expect.loc);
               }
             }
-      });
+          },
+      );
     });
   });
 });

packages/babel-helper-bindify-decorators/src/index.js

@@ -1,7 +1,9 @@
 import type { NodePath } from "babel-traverse";
 import * as t from "babel-types";
 
-export default function bindifyDecorators(decorators: Array<NodePath>): Array<NodePath> {
+export default function bindifyDecorators(
+  decorators: Array<NodePath>,
+): Array<NodePath> {
   for (const decoratorPath of decorators) {
     const decorator = decoratorPath.node;
     const expression = decorator.expression;
@@ -19,13 +21,15 @@ export default function bindifyDecorators(decorators: Array<NodePath>): Array<No
       ref = expression.object;
     }
 
-    nodes.push(t.callExpression(
+    nodes.push(
+      t.callExpression(
         t.memberExpression(
           t.memberExpression(ref, expression.property, expression.computed),
-        t.identifier("bind")
+          t.identifier("bind"),
         ),
-      [ref]
+        [ref],
-    ));
+      ),
+    );
 
     if (nodes.length === 1) {
       decorator.expression = nodes[0];

packages/babel-helper-builder-binary-assignment-operator-visitor/src/index.js

@@ -1,10 +1,7 @@
 import explode from "babel-helper-explode-assignable-expression";
 import * as t from "babel-types";
 
-export default function (opts: {
+export default function(opts: { build: Function, operator: string }): Object {
-  build: Function;
-  operator: string;
-}): Object {
   const visitor = {};
 
   function isAssignment(node) {
@@ -15,7 +12,7 @@ export default function (opts: {
     return t.assignmentExpression("=", left, right);
   }
 
-  visitor.ExpressionStatement = function (path, file) {
+  visitor.ExpressionStatement = function(path, file) {
     // hit the `AssignmentExpression` one below
     if (path.isCompletionRecord()) return;
 
@@ -25,24 +22,28 @@ export default function (opts: {
     const nodes = [];
     const exploded = explode(expr.left, nodes, file, path.scope, true);
 
-    nodes.push(t.expressionStatement(
+    nodes.push(
-      buildAssignment(exploded.ref, opts.build(exploded.uid, expr.right))
+      t.expressionStatement(
-    ));
+        buildAssignment(exploded.ref, opts.build(exploded.uid, expr.right)),
+      ),
+    );
 
     path.replaceWithMultiple(nodes);
   };
 
-  visitor.AssignmentExpression = function (path, file) {
+  visitor.AssignmentExpression = function(path, file) {
     const { node, scope } = path;
     if (!isAssignment(node)) return;
 
     const nodes = [];
     const exploded = explode(node.left, nodes, file, scope);
-    nodes.push(buildAssignment(exploded.ref, opts.build(exploded.uid, node.right)));
+    nodes.push(
+      buildAssignment(exploded.ref, opts.build(exploded.uid, node.right)),
+    );
     path.replaceWithMultiple(nodes);
   };
 
-  visitor.BinaryExpression = function (path) {
+  visitor.BinaryExpression = function(path) {
     const { node } = path;
     if (node.operator === opts.operator) {
       path.replaceWith(opts.build(node.left, node.right));

packages/babel-helper-builder-react-jsx/src/index.js

@@ -2,19 +2,21 @@ import esutils from "esutils";
 import * as t from "babel-types";
 
 type ElementState = {
-  tagExpr: Object; // tag node
+  tagExpr: Object, // tag node
-  tagName: string; // raw string tag name
+  tagName: string, // raw string tag name
-  args: Array<Object>; // array of call arguments
+  args: Array<Object>, // array of call arguments
-  call?: Object; // optional call property that can be set to override the call expression returned
+  call?: Object, // optional call property that can be set to override the call expression returned
-  pre?: Function; // function called with (state: ElementState) before building attribs
+  pre?: Function, // function called with (state: ElementState) before building attribs
-  post?: Function; // function called with (state: ElementState) after building attribs
+  post?: Function, // function called with (state: ElementState) after building attribs
 };
 
-export default function (opts) {
+export default function(opts) {
   const visitor = {};
 
-  visitor.JSXNamespacedName = function (path) {
+  visitor.JSXNamespacedName = function(path) {
-    throw path.buildCodeFrameError("Namespace tags are not supported. ReactJSX is not XML.");
+    throw path.buildCodeFrameError(
+      "Namespace tags are not supported. ReactJSX is not XML.",
+    );
   };
 
   visitor.JSXElement = {
@@ -45,7 +47,7 @@ export default function (opts) {
     } else if (t.isJSXMemberExpression(node)) {
       return t.memberExpression(
         convertJSXIdentifier(node.object, node),
-        convertJSXIdentifier(node.property, node)
+        convertJSXIdentifier(node.property, node),
       );
     }
 
@@ -127,7 +129,6 @@ export default function (opts) {
     return [];
   }
 
-
   /**
    * The logic for this is quite terse. It's because we need to
    * support spread elements. We loop over all attributes,
@@ -141,8 +142,10 @@ export default function (opts) {
 
     const useBuiltIns = file.opts.useBuiltIns || false;
     if (typeof useBuiltIns !== "boolean") {
-      throw new Error("transform-react-jsx currently only accepts a boolean option for " +
+      throw new Error(
-        "useBuiltIns (defaults to false)");
+        "transform-react-jsx currently only accepts a boolean option for " +
+          "useBuiltIns (defaults to false)",
+      );
     }
 
     while (attribs.length) {
@@ -166,9 +169,9 @@ export default function (opts) {
         objs.unshift(t.objectExpression([]));
       }
 
-      const helper = useBuiltIns ?
+      const helper = useBuiltIns
-        t.memberExpression(t.identifier("Object"), t.identifier("assign")) :
+        ? t.memberExpression(t.identifier("Object"), t.identifier("assign"))
-        file.addHelper("extends");
+        : file.addHelper("extends");
 
       // spread it
       attribs = t.callExpression(helper, objs);

packages/babel-helper-call-delegate/src/index.js

@@ -18,15 +18,21 @@ const visitor = {
   },
 };
 
-export default function (path: NodePath, scope = path.scope) {
+export default function(path: NodePath, scope = path.scope) {
   const { node } = path;
-  const container = t.functionExpression(null, [], node.body, node.generator, node.async);
+  const container = t.functionExpression(
+    null,
+    [],
+    node.body,
+    node.generator,
+    node.async,
+  );
 
   let callee = container;
   let args = [];
 
   // todo: only hoist if necessary
-  hoistVariables(path, (id) => scope.push({ id }));
+  hoistVariables(path, id => scope.push({ id }));
 
   const state = {
     foundThis: false,

packages/babel-helper-define-map/src/index.js

@@ -12,7 +12,13 @@ function toKind(node: Object) {
   return "value";
 }
 
-export function push(mutatorMap: Object, node: Object, kind: string, file, scope?): Object {
+export function push(
+  mutatorMap: Object,
+  node: Object,
+  kind: string,
+  file,
+  scope?,
+): Object {
   const alias = t.toKeyAlias(node);
 
   //
@@ -33,9 +39,11 @@ export function push(mutatorMap: Object, node: Object, kind: string, file, scope
   }
 
   if (node.decorators) {
-    const decorators = map.decorators = map.decorators || t.arrayExpression([]);
+    const decorators = (map.decorators =
+      map.decorators || t.arrayExpression([]));
     decorators.elements = decorators.elements.concat(
-      node.decorators.map((dec) => dec.expression).reverse());
+      node.decorators.map(dec => dec.expression).reverse(),
+    );
   }
 
   if (map.value || map.initializer) {
@@ -45,14 +53,24 @@ export function push(mutatorMap: Object, node: Object, kind: string, file, scope
   let key, value;
 
   // save the key so we can possibly do function name inferences
-  if (t.isObjectProperty(node) || t.isObjectMethod(node) || t.isClassMethod(node)) {
+  if (
+    t.isObjectProperty(node) ||
+    t.isObjectMethod(node) ||
+    t.isClassMethod(node)
+  ) {
     key = t.toComputedKey(node, node.key);
   }
 
   if (t.isObjectProperty(node) || t.isClassProperty(node)) {
     value = node.value;
   } else if (t.isObjectMethod(node) || t.isClassMethod(node)) {
-    value = t.functionExpression(null, node.params, node.body, node.generator, node.async);
+    value = t.functionExpression(
+      null,
+      node.params,
+      node.body,
+      node.generator,
+      node.async,
+    );
     value.returnType = node.returnType;
   }
 
@@ -62,8 +80,12 @@ export function push(mutatorMap: Object, node: Object, kind: string, file, scope
   }
 
   // infer function name
-  if (scope && t.isStringLiteral(key) && (kind === "value" || kind === "initializer") &&
+  if (
-    t.isFunctionExpression(value)) {
+    scope &&
+    t.isStringLiteral(key) &&
+    (kind === "value" || kind === "initializer") &&
+    t.isFunctionExpression(value)
+  ) {
     value = nameFunction({ id: key, node: value, scope });
   }
 
@@ -90,7 +112,9 @@ export function toComputedObjectFromClass(obj: Object): Object {
   for (let i = 0; i < obj.properties.length; i++) {
     const prop = obj.properties[i];
     const val = prop.value;
-    val.properties.unshift(t.objectProperty(t.identifier("key"), t.toComputedKey(prop)));
+    val.properties.unshift(
+      t.objectProperty(t.identifier("key"), t.toComputedKey(prop)),
+    );
     objExpr.elements.push(val);
   }
 
@@ -100,13 +124,13 @@ export function toComputedObjectFromClass(obj: Object): Object {
 export function toClassObject(mutatorMap: Object): Object {
   const objExpr = t.objectExpression([]);
 
-  Object.keys(mutatorMap).forEach(function (mutatorMapKey) {
+  Object.keys(mutatorMap).forEach(function(mutatorMapKey) {
     const map = mutatorMap[mutatorMapKey];
     const mapNode = t.objectExpression([]);
 
     const propNode = t.objectProperty(map._key, mapNode, map._computed);
 
-    Object.keys(map).forEach(function (key) {
+    Object.keys(map).forEach(function(key) {
       let node = map[key];
       if (key[0] === "_") return;
 
@@ -127,7 +151,7 @@ export function toClassObject(mutatorMap: Object): Object {
 }
 
 export function toDefineObject(mutatorMap: Object): Object {
-  Object.keys(mutatorMap).forEach(function (key) {
+  Object.keys(mutatorMap).forEach(function(key) {
     const map = mutatorMap[key];
     if (map.value) map.writable = t.booleanLiteral(true);
     map.configurable = t.booleanLiteral(true);

packages/babel-helper-explode-assignable-expression/src/index.js

@@ -20,7 +20,7 @@ function getObjRef(node, nodes, file, scope) {
   } else if (t.isMemberExpression(node)) {
     ref = node.object;
 
-    if (t.isSuper(ref) || t.isIdentifier(ref) && scope.hasBinding(ref.name)) {
+    if (t.isSuper(ref) || (t.isIdentifier(ref) && scope.hasBinding(ref.name))) {
       // the object reference that we need to save is locally declared
       // so as per the previous comment we can be 100% sure evaluating
       // it multiple times will be safe
@@ -32,9 +32,7 @@ function getObjRef(node, nodes, file, scope) {
   }
 
   const temp = scope.generateUidIdentifierBasedOnNode(ref);
-  nodes.push(t.variableDeclaration("var", [
+  nodes.push(t.variableDeclaration("var", [t.variableDeclarator(temp, ref)]));
-    t.variableDeclarator(temp, ref),
-  ]));
   return temp;
 }
 
@@ -44,21 +42,19 @@ function getPropRef(node, nodes, file, scope) {
   if (t.isLiteral(key) && t.isPureish(key)) return key;
 
   const temp = scope.generateUidIdentifierBasedOnNode(prop);
-  nodes.push(t.variableDeclaration("var", [
+  nodes.push(t.variableDeclaration("var", [t.variableDeclarator(temp, prop)]));
-    t.variableDeclarator(temp, prop),
-  ]));
   return temp;
 }
 
-export default function (
+export default function(
   node: Object,
   nodes: Array<Object>,
   file,
   scope: Scope,
   allowedSingleIdent?: boolean,
 ): {
-  uid: Object;
+  uid: Object,
-  ref: Object;
+  ref: Object,
 } {
   let obj;
   if (t.isIdentifier(node) && allowedSingleIdent) {

packages/babel-helper-explode-class/src/index.js

@@ -2,7 +2,7 @@ import bindifyDecorators from "babel-helper-bindify-decorators";
 import type { NodePath } from "babel-traverse";
 import * as t from "babel-types";
 
-export default function (classPath) {
+export default function(classPath) {
   classPath.assertClass();
 
   const memoisedExpressions = [];
@@ -44,6 +44,8 @@ export default function (classPath) {
   }
 
   if (memoisedExpressions) {
-    classPath.insertBefore(memoisedExpressions.map((expr) => t.expressionStatement(expr)));
+    classPath.insertBefore(
+      memoisedExpressions.map(expr => t.expressionStatement(expr)),
+    );
   }
 }

packages/babel-helper-fixtures/src/index.js

@@ -15,25 +15,25 @@ function humanize(val, noext) {
 }
 
 type TestFile = {
-  loc: string;
+  loc: string,
-  code: string;
+  code: string,
-  filename: string;
+  filename: string,
 };
 
 type Test = {
-  title: string;
+  title: string,
-  disabled: boolean;
+  disabled: boolean,
-  options: Object;
+  options: Object,
-  exec: TestFile;
+  exec: TestFile,
-  actual: TestFile;
+  actual: TestFile,
-  expected: TestFile;
+  expected: TestFile,
 };
 
 type Suite = {
-  options: Object;
+  options: Object,
-  tests: Array<Test>;
+  tests: Array<Test>,
-  title: string;
+  title: string,
-  filename: string;
+  filename: string,
 };
 
 function assertDirectory(loc) {
@@ -50,7 +50,9 @@ function shouldIgnore(name, blacklist?: Array<string>) {
   const ext = path.extname(name);
   const base = path.basename(name, ext);
 
-  return name[0] === "." || ext === ".md" || base === "LICENSE" || base === "options";
+  return (
+    name[0] === "." || ext === ".md" || base === "LICENSE" || base === "options"
+  );
 }
 
 export default function get(entryLoc): Array<Suite> {
@@ -133,7 +135,9 @@ export default function get(entryLoc): Array<Suite> {
         const minimumVersion = semver.clean(taskOpts.minNodeVersion);
 
         if (minimumVersion == null) {
-          throw new Error(`'minNodeVersion' has invalid semver format: ${taskOpts.minNodeVersion}`);
+          throw new Error(
+            `'minNodeVersion' has invalid semver format: ${taskOpts.minNodeVersion}`,
+          );
         }
 
         if (semver.lt(nodeVersion, minimumVersion)) {

packages/babel-helper-function-name/src/index.js

@@ -56,7 +56,9 @@ function wrap(state, method, id, scope) {
 
       // need to add a wrapper since we can't change the references
       let build = buildPropertyMethodAssignmentWrapper;
-      if (method.generator) build = buildGeneratorPropertyMethodAssignmentWrapper;
+      if (method.generator) {
+        build = buildGeneratorPropertyMethodAssignmentWrapper;
+      }
       const template = build({
         FUNCTION: method,
         FUNCTION_ID: id,
@@ -125,12 +127,15 @@ function visit(node, name, scope) {
   return state;
 }
 
-export default function ({ node, parent, scope, id }) {
+export default function({ node, parent, scope, id }) {
   // has an `id` so we don't need to infer one
   if (node.id) return;
 
-  if ((t.isObjectProperty(parent) || t.isObjectMethod(parent, { kind: "method" })) &&
+  if (
-    (!parent.computed || t.isLiteral(parent.key))) {
+    (t.isObjectProperty(parent) ||
+      t.isObjectMethod(parent, { kind: "method" })) &&
+    (!parent.computed || t.isLiteral(parent.key))
+  ) {
     // { foo() {} };
     id = parent.key;
   } else if (t.isVariableDeclarator(parent)) {
@@ -139,7 +144,11 @@ export default function ({ node, parent, scope, id }) {
 
     if (t.isIdentifier(id)) {
       const binding = scope.parent.getBinding(id.name);
-      if (binding && binding.constant && scope.getBinding(id.name) === binding) {
+      if (
+        binding &&
+        binding.constant &&
+        scope.getBinding(id.name) === binding
+      ) {
         // always going to reference this method
         node.id = id;
         node.id[t.NOT_LOCAL_BINDING] = true;

packages/babel-helper-get-function-arity/src/index.js

@@ -1,6 +1,6 @@
 import * as t from "babel-types";
 
-export default function (node): number {
+export default function(node): number {
   const params: Array<Object> = node.params;
   for (let i = 0; i < params.length; i++) {
     const param = params[i];

packages/babel-helper-hoist-variables/src/index.js

@@ -21,9 +21,11 @@ const visitor = {
       firstId = declar.node.id;
 
       if (declar.node.init) {
-        nodes.push(t.expressionStatement(
+        nodes.push(
-          t.assignmentExpression("=", declar.node.id, declar.node.init)
+          t.expressionStatement(
-        ));
+            t.assignmentExpression("=", declar.node.id, declar.node.init),
+          ),
+        );
       }
 
       for (const name in declar.getBindingIdentifiers()) {
@@ -40,6 +42,6 @@ const visitor = {
   },
 };
 
-export default function (path, emit: Function, kind: "var" | "let" = "var") {
+export default function(path, emit: Function, kind: "var" | "let" = "var") {
   path.traverse(visitor, { kind, emit });
 }

packages/babel-helper-optimise-call-expression/src/index.js

@@ -1,17 +1,20 @@
 import * as t from "babel-types";
 
-export default function (callee, thisNode, args) {
+export default function(callee, thisNode, args) {
-  if (args.length === 1 && t.isSpreadElement(args[0]) &&
+  if (
-    t.isIdentifier(args[0].argument, { name: "arguments" })) {
+    args.length === 1 &&
+    t.isSpreadElement(args[0]) &&
+    t.isIdentifier(args[0].argument, { name: "arguments" })
+  ) {
     // eg. super(...arguments);
-    return t.callExpression(
+    return t.callExpression(t.memberExpression(callee, t.identifier("apply")), [
-      t.memberExpression(callee, t.identifier("apply")),
+      thisNode,
-      [thisNode, args[0].argument]
+      args[0].argument,
-    );
+    ]);
   } else {
-    return t.callExpression(
+    return t.callExpression(t.memberExpression(callee, t.identifier("call")), [
-      t.memberExpression(callee, t.identifier("call")),
+      thisNode,
-      [thisNode, ...args]
+      ...args,
-    );
+    ]);
   }
 }

packages/babel-helper-plugin-test-runner/src/index.js

@@ -1,7 +1,7 @@
 import testRunner from "babel-helper-transform-fixture-test-runner";
 import path from "path";
 
-export default function (loc) {
+export default function(loc) {
   const name = path.basename(path.dirname(loc));
   testRunner(loc + "/fixtures", name);
 }

packages/babel-helper-remap-async-to-generator/src/for-await.js

@@ -48,13 +48,17 @@ const forAwaitVisitor = {
     const callee = path.node.callee;
 
     // if no await wrapping is being applied, unwrap the call expression
-    if (t.isIdentifier(callee) && callee.name === "AWAIT" && !replacements.AWAIT) {
+    if (
+      t.isIdentifier(callee) &&
+      callee.name === "AWAIT" &&
+      !replacements.AWAIT
+    ) {
       path.replaceWith(path.node.arguments[0]);
     }
   },
 };
 
-export default function (path, helpers) {
+export default function(path, helpers) {
   const { node, scope, parent } = path;
 
   const stepKey = scope.generateUidIdentifier("step");
@@ -64,7 +68,9 @@ export default function (path, helpers) {
 
   if (t.isIdentifier(left) || t.isPattern(left) || t.isMemberExpression(left)) {
     // for await (i of test), for await ({ i } of test)
-    declar = t.expressionStatement(t.assignmentExpression("=", left, stepValue));
+    declar = t.expressionStatement(
+      t.assignmentExpression("=", left, stepValue),
+    );
   } else if (t.isVariableDeclaration(left)) {
     // for await (let i of test)
     declar = t.variableDeclaration(left.kind, [
@@ -76,7 +82,9 @@ export default function (path, helpers) {
 
   traverse(template, forAwaitVisitor, null, {
     ITERATOR_HAD_ERROR_KEY: scope.generateUidIdentifier("didIteratorError"),
-    ITERATOR_COMPLETION: scope.generateUidIdentifier("iteratorNormalCompletion"),
+    ITERATOR_COMPLETION: scope.generateUidIdentifier(
+      "iteratorNormalCompletion",
+    ),
     ITERATOR_ERROR_KEY: scope.generateUidIdentifier("iteratorError"),
     ITERATOR_KEY: scope.generateUidIdentifier("iterator"),
     GET_ITERATOR: helpers.getAsyncIterator,

packages/babel-helper-remap-async-to-generator/src/index.js

@@ -70,7 +70,6 @@ const awaitVisitor = {
       path.replaceWithMultiple(build.node);
     }
   },
-
 };
 
 function classOrObjectMethod(path: NodePath, callId: Object) {
@@ -79,12 +78,16 @@ function classOrObjectMethod(path: NodePath, callId: Object) {
 
   node.async = false;
 
-  const container = t.functionExpression(null, [], t.blockStatement(body.body), true);
+  const container = t.functionExpression(
+    null,
+    [],
+    t.blockStatement(body.body),
+    true,
+  );
   body.body = [
-    t.returnStatement(t.callExpression(
+    t.returnStatement(
-      t.callExpression(callId, [container]),
+      t.callExpression(t.callExpression(callId, [container]), []),
-      []
+    ),
-    )),
   ];
 
   // Regardless of whether or not the wrapped function is a an async method
@@ -92,7 +95,9 @@ function classOrObjectMethod(path: NodePath, callId: Object) {
   node.generator = false;
 
   // Unwrap the wrapper IIFE's environment so super and this and such still work.
-  path.get("body.body.0.argument.callee.arguments.0").unwrapFunctionEnvironment();
+  path
+    .get("body.body.0.argument.callee.arguments.0")
+    .unwrapFunctionEnvironment();
 }
 
 function plainFunction(path: NodePath, callId: Object) {
@@ -121,25 +126,29 @@ function plainFunction(path: NodePath, callId: Object) {
     NAME: asyncFnId || null,
     REF: path.scope.generateUidIdentifier("ref"),
     FUNCTION: built,
-    PARAMS: node.params.reduce((acc, param) => {
+    PARAMS: node.params.reduce(
-      acc.done = acc.done || t.isAssignmentPattern(param) || t.isRestElement(param);
+      (acc, param) => {
+        acc.done =
+          acc.done || t.isAssignmentPattern(param) || t.isRestElement(param);
 
         if (!acc.done) {
           acc.params.push(path.scope.generateUidIdentifier("x"));
         }
 
         return acc;
-    }, {
+      },
+      {
         params: [],
         done: false,
-    }).params,
+      },
+    ).params,
   }).expression;
 
   if (isDeclaration) {
     const declar = t.variableDeclaration("let", [
       t.variableDeclarator(
         t.identifier(asyncFnId.name),
-        t.callExpression(container, [])
+        t.callExpression(container, []),
       ),
     ]);
     declar._blockHoist = true;
@@ -149,14 +158,12 @@ function plainFunction(path: NodePath, callId: Object) {
       // the identifier into an expressionStatement
       path.parentPath.insertBefore(declar);
       path.parentPath.replaceWith(
-        t.exportNamedDeclaration(null,
+        t.exportNamedDeclaration(null, [
-          [
           t.exportSpecifier(
             t.identifier(asyncFnId.name),
-              t.identifier("default")
+            t.identifier("default"),
           ),
-          ]
+        ]),
-        )
       );
       return;
     }
@@ -182,7 +189,7 @@ function plainFunction(path: NodePath, callId: Object) {
   }
 }
 
-export default function (path: NodePath, file: Object, helpers: Object) {
+export default function(path: NodePath, file: Object, helpers: Object) {
   if (!helpers) {
     // bc for 6.15 and earlier
     helpers = { wrapAsync: file };

packages/babel-helper-replace-supers/src/index.js

@@ -30,16 +30,19 @@ function isMemberExpressionSuper(node) {
  *   CLASS.prototype.__proto__ || Object.getPrototypeOf(CLASS.prototype)
  */
 function getPrototypeOfExpression(objectRef, isStatic) {
-  const targetRef = isStatic ? objectRef : t.memberExpression(objectRef, t.identifier("prototype"));
+  const targetRef = isStatic
+    ? objectRef
+    : t.memberExpression(objectRef, t.identifier("prototype"));
 
   return t.logicalExpression(
     "||",
     t.memberExpression(targetRef, t.identifier("__proto__")),
     t.callExpression(
-      t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
+      t.memberExpression(
-      [
+        t.identifier("Object"),
-        targetRef,
+        t.identifier("getPrototypeOf"),
-      ]
+      ),
+      [targetRef],
     ),
   );
 }
@@ -119,14 +122,14 @@ export default class ReplaceSupers {
   scope: Scope;
   file;
   opts: {
-    forceSuperMemoisation: boolean;
+    forceSuperMemoisation: boolean,
-    getObjetRef: Function;
+    getObjetRef: Function,
-    methodPath: NodePath;
+    methodPath: NodePath,
-    methodNode: Object;
+    methodNode: Object,
-    superRef: Object;
+    superRef: Object,
-    isStatic: boolean;
+    isStatic: boolean,
-    isLoose: boolean;
+    isLoose: boolean,
-    file: any;
+    file: any,
   };
 
   getObjectRef() {
@@ -143,16 +146,17 @@ export default class ReplaceSupers {
    *
    */
 
-  setSuperProperty(property: Object, value: Object, isComputed: boolean): Object {
+  setSuperProperty(
-    return t.callExpression(
+    property: Object,
-      this.file.addHelper("set"),
+    value: Object,
-      [
+    isComputed: boolean,
+  ): Object {
+    return t.callExpression(this.file.addHelper("set"), [
       getPrototypeOfExpression(this.getObjectRef(), this.isStatic),
       isComputed ? property : t.stringLiteral(property.name),
       value,
       t.thisExpression(),
-      ]
+    ]);
-    );
   }
 
   /**
@@ -165,14 +169,11 @@ export default class ReplaceSupers {
    */
 
   getSuperProperty(property: Object, isComputed: boolean): Object {
-    return t.callExpression(
+    return t.callExpression(this.file.addHelper("get"), [
-      this.file.addHelper("get"),
-      [
       getPrototypeOfExpression(this.getObjectRef(), this.isStatic),
       isComputed ? property : t.stringLiteral(property.name),
       t.thisExpression(),
-      ]
+    ]);
-    );
   }
 
   replace() {
@@ -214,16 +215,23 @@ export default class ReplaceSupers {
   specHandleAssignmentExpression(ref, path, node) {
     if (node.operator === "=") {
       // super.name = "val"; -> _set(Object.getPrototypeOf(objectRef.prototype), "name", this);
-      return this.setSuperProperty(node.left.property, node.right, node.left.computed);
+      return this.setSuperProperty(
+        node.left.property,
+        node.right,
+        node.left.computed,
+      );
     } else {
       // super.age += 2; -> let _ref = super.age; super.age = _ref + 2;
       ref = ref || path.scope.generateUidIdentifier("ref");
       return [
-        t.variableDeclaration("var", [
+        t.variableDeclaration("var", [t.variableDeclarator(ref, node.left)]),
-          t.variableDeclarator(ref, node.left),
+        t.expressionStatement(
-        ]),
+          t.assignmentExpression(
-        t.expressionStatement(t.assignmentExpression("=", node.left,
+            "=",
-          t.binaryExpression(node.operator.slice(0, -1), ref, node.right))),
+            node.left,
+            t.binaryExpression(node.operator.slice(0, -1), ref, node.right),
+          ),
+        ),
       ];
     }
   }
@@ -258,8 +266,15 @@ export default class ReplaceSupers {
       // _get(Object.getPrototypeOf(objectRef.prototype), "name", this);
       property = node.property;
       computed = node.computed;
-    } else if (t.isUpdateExpression(node) && isMemberExpressionSuper(node.argument)) {
+    } else if (
-      const binary = t.assignmentExpression(node.operator[0] + "=", node.argument, t.numericLiteral(1));
+      t.isUpdateExpression(node) &&
+      isMemberExpressionSuper(node.argument)
+    ) {
+      const binary = t.assignmentExpression(
+        node.operator[0] + "=",
+        node.argument,
+        t.numericLiteral(1),
+      );
       if (node.prefix) {
         // ++super.foo;
         // to
@@ -270,9 +285,14 @@ export default class ReplaceSupers {
         // to
         // let _ref = super.foo; super.foo = _ref + 1;
         const ref = path.scope.generateUidIdentifier("ref");
-        return this.specHandleAssignmentExpression(ref, path, binary).concat(t.expressionStatement(ref));
+        return this.specHandleAssignmentExpression(ref, path, binary).concat(
+          t.expressionStatement(ref),
+        );
       }
-    } else if (t.isAssignmentExpression(node) && isMemberExpressionSuper(node.left)) {
+    } else if (
+      t.isAssignmentExpression(node) &&
+      isMemberExpressionSuper(node.left)
+    ) {
       return this.specHandleAssignmentExpression(null, path, node);
     }
 

packages/babel-helper-transform-fixture-test-runner/src/helpers.js

@@ -4,13 +4,9 @@ export function assertNoOwnProperties(obj) {
   assert.equal(Object.getOwnPropertyNames(obj).length, 0);
 }
 
-export function assertHasOwnProperty() {
+export function assertHasOwnProperty() {}
 
-}
+export function assertLacksOwnProperty() {}
-
-export function assertLacksOwnProperty() {
-
-}
 
 export function multiline(arr) {
   return arr.join("\n");

packages/babel-helper-transform-fixture-test-runner/src/index.js

@@ -38,7 +38,9 @@ runCodeInTestContext(buildExternalHelpers());
  * This allows us to run our unittests
  */
 function runModuleInTestContext(id: string, relativeFilename: string) {
-  const filename = resolve.sync(id, { basedir: path.dirname(relativeFilename) });
+  const filename = resolve.sync(id, {
+    basedir: path.dirname(relativeFilename),
+  });
 
   // Expose Node-internal modules if the tests want them. Note, this will not execute inside
   // the context's global scope.
@@ -46,20 +48,22 @@ function runModuleInTestContext(id: string, relativeFilename: string) {
 
   if (moduleCache[filename]) return moduleCache[filename].exports;
 
-  const module = moduleCache[filename] = {
+  const module = (moduleCache[filename] = {
     id: filename,
     exports: {},
-  };
+  });
   const dirname = path.dirname(filename);
-  const req = (id) => runModuleInTestContext(id, filename);
+  const req = id => runModuleInTestContext(id, filename);
 
   const src = fs.readFileSync(filename, "utf8");
   const code = `(function (exports, require, module, __filename, __dirname) {${src}\n});`;
 
-  vm.runInContext(code, testContext, {
+  vm
+    .runInContext(code, testContext, {
       filename,
       displayErrors: true,
-  }).call(module.exports, module.exports, req, module, filename, dirname);
+    })
+    .call(module.exports, module.exports, req, module, filename, dirname);
 
   return module.exports;
 }
@@ -69,10 +73,13 @@ function runModuleInTestContext(id: string, relativeFilename: string) {
  *
  * Exposed for unit tests, not for use as an API.
  */
-export function runCodeInTestContext(code: string, opts: {filename?: string} = {}) {
+export function runCodeInTestContext(
+  code: string,
+  opts: { filename?: string } = {},
+) {
   const filename = opts.filename || null;
   const dirname = filename ? path.dirname(filename) : null;
-  const req = filename ? ((id) => runModuleInTestContext(id, filename)) : null;
+  const req = filename ? id => runModuleInTestContext(id, filename) : null;
 
   const module = {
     id: filename,
@@ -90,21 +97,21 @@ export function runCodeInTestContext(code: string, opts: {filename?: string} = {
 }
 
 function wrapPackagesArray(type, names, optionsDir) {
-  return (names || []).map(function (val) {
+  return (names || []).map(function(val) {
     if (typeof val === "string") val = [val];
 
     // relative path (outside of monorepo)
     if (val[0][0] === ".") {
-
       if (!optionsDir) {
-        throw new Error("Please provide an options.json in test dir when using a " +
+        throw new Error(
-          "relative plugin path.");
+          "Please provide an options.json in test dir when using a " +
+            "relative plugin path.",
+        );
       }
 
       val[0] = path.resolve(optionsDir, val[0]);
-    }
+    } else {
       // check node_modules/babel-x-y
-    else {
       val[0] = __dirname + "/../../babel-" + type + "-" + val[0];
     }
 
@@ -120,15 +127,25 @@ function run(task) {
   const optionsDir = task.optionsDir;
 
   function getOpts(self) {
-    const newOpts = merge({
+    const newOpts = merge(
+      {
         filename: self.loc,
-    }, opts);
+      },
+      opts,
+    );
 
     newOpts.plugins = wrapPackagesArray("plugin", newOpts.plugins, optionsDir);
-    newOpts.presets = wrapPackagesArray("preset", newOpts.presets, optionsDir).map(function (val) {
+    newOpts.presets = wrapPackagesArray(
+      "preset",
+      newOpts.presets,
+      optionsDir,
+    ).map(function(val) {
       if (val.length > 2) {
-        throw new Error("Unexpected extra options " + JSON.stringify(val.slice(2)) +
+        throw new Error(
-          " passed to preset.");
+          "Unexpected extra options " +
+            JSON.stringify(val.slice(2)) +
+            " passed to preset.",
+        );
       }
 
       return val;
@@ -160,14 +177,19 @@ function run(task) {
   if (!execCode || actualCode) {
     result = babel.transform(actualCode, getOpts(actual));
     if (
-      !expect.code && result.code && !opts.throws && fs.statSync(path.dirname(expect.loc)).isDirectory() &&
+      !expect.code &&
+      result.code &&
+      !opts.throws &&
+      fs.statSync(path.dirname(expect.loc)).isDirectory() &&
       !process.env.CI
     ) {
       console.log(`New test file created: ${expect.loc}`);
       fs.writeFileSync(expect.loc, result.code);
     } else {
       actualCode = result.code.trim();
-      chai.expect(actualCode).to.be.equal(expectCode, actual.loc + " !== " + expect.loc);
+      chai
+        .expect(actualCode)
+        .to.be.equal(expectCode, actual.loc + " !== " + expect.loc);
     }
   }
 
@@ -178,11 +200,13 @@ function run(task) {
   if (task.sourceMappings) {
     const consumer = new sourceMap.SourceMapConsumer(result.map);
 
-    task.sourceMappings.forEach(function (mapping) {
+    task.sourceMappings.forEach(function(mapping) {
       const actual = mapping.original;
 
       const expect = consumer.originalPositionFor(mapping.generated);
-      chai.expect({ line: expect.line, column: expect.column }).to.deep.equal(actual);
+      chai
+        .expect({ line: expect.line, column: expect.column })
+        .to.deep.equal(actual);
     });
   }
 
@@ -191,7 +215,7 @@ function run(task) {
   }
 }
 
-export default function (
+export default function(
   fixturesLoc: string,
   name: string,
   suiteOpts = {},
@@ -203,12 +227,19 @@ export default function (
   for (const testSuite of suites) {
     if (includes(suiteOpts.ignoreSuites, testSuite.title)) continue;
 
-    describe(name + "/" + testSuite.title, function () {
+    describe(name + "/" + testSuite.title, function() {
       for (const task of testSuite.tests) {
-        if (includes(suiteOpts.ignoreTasks, task.title) ||
+        if (
-            includes(suiteOpts.ignoreTasks, testSuite.title + "/" + task.title)) continue;
+          includes(suiteOpts.ignoreTasks, task.title) ||
+          includes(suiteOpts.ignoreTasks, testSuite.title + "/" + task.title)
+        ) {
+          continue;
+        }
 
-        it(task.title, !task.disabled && function () {
+        it(
+          task.title,
+          !task.disabled &&
+            function() {
               function runTask() {
                 run(task);
               }
@@ -232,8 +263,10 @@ export default function (
                 // the options object with useless options
                 delete task.options.throws;
 
-            assert.throws(runTask, function (err) {
+                assert.throws(runTask, function(err) {
-              return throwMsg === true || err.message.indexOf(throwMsg) >= 0;
+                  return (
+                    throwMsg === true || err.message.indexOf(throwMsg) >= 0
+                  );
                 });
               } else {
                 if (task.exec.code) {
@@ -245,7 +278,8 @@ export default function (
                   runTask();
                 }
               }
-        });
+            },
+        );
       }
     });
   }

packages/babel-helpers/src/helpers.js

@@ -359,7 +359,6 @@ helpers.get = template(`
   });
 `);
 
-
 helpers.inherits = template(`
   (function (subClass, superClass) {
     if (typeof superClass !== "function" && superClass !== null) {
@@ -395,7 +394,6 @@ helpers.instanceof = template(`
   });
 `);
 
-
 helpers.interopRequireDefault = template(`
   (function (obj) {
     return obj && obj.__esModule ? obj : { default: obj };

packages/babel-helpers/src/index.js

@@ -8,7 +8,7 @@ export function get(name) {
 }
 
 export const list = Object.keys(helpers)
-  .map((name) => name.replace(/^_/, ""))
+  .map(name => name.replace(/^_/, ""))
-  .filter((name) => name !== "__esModule");
+  .filter(name => name !== "__esModule");
 
 export default get;

packages/babel-messages/src/index.js

@@ -8,38 +8,55 @@ import * as util from "util";
  */
 
 export const MESSAGES = {
-  tailCallReassignmentDeopt: "Function reference has been reassigned, so it will probably be dereferenced, therefore we can't optimise this with confidence",
+  tailCallReassignmentDeopt:
+    "Function reference has been reassigned, so it will probably be dereferenced, therefore we can't optimise this with confidence",
   classesIllegalBareSuper: "Illegal use of bare super",
-  classesIllegalSuperCall: "Direct super call is illegal in non-constructor, use super.$1() instead",
+  classesIllegalSuperCall:
+    "Direct super call is illegal in non-constructor, use super.$1() instead",
   scopeDuplicateDeclaration: "Duplicate declaration $1",
   settersNoRest: "Setters aren't allowed to have a rest",
   noAssignmentsInForHead: "No assignments allowed in for-in/of head",
-  expectedMemberExpressionOrIdentifier: "Expected type MemberExpression or Identifier",
+  expectedMemberExpressionOrIdentifier:
-  invalidParentForThisNode: "We don't know how to handle this node within the current parent - please open an issue",
+    "Expected type MemberExpression or Identifier",
+  invalidParentForThisNode:
+    "We don't know how to handle this node within the current parent - please open an issue",
   readOnly: "$1 is read-only",
   unknownForHead: "Unknown node type $1 in ForStatement",
   didYouMean: "Did you mean $1?",
-  codeGeneratorDeopt: "Note: The code generator has deoptimised the styling of $1 as it exceeds the max of $2.",
+  codeGeneratorDeopt:
-  missingTemplatesDirectory: "no templates directory - this is most likely the result of a broken `npm publish`. Please report to https://github.com/babel/babel/issues",
+    "Note: The code generator has deoptimised the styling of $1 as it exceeds the max of $2.",
+  missingTemplatesDirectory:
+    "no templates directory - this is most likely the result of a broken `npm publish`. Please report to https://github.com/babel/babel/issues",
   unsupportedOutputType: "Unsupported output type $1",
   illegalMethodName: "Illegal method name $1",
-  lostTrackNodePath: "We lost track of this node's position, likely because the AST was directly manipulated",
+  lostTrackNodePath:
+    "We lost track of this node's position, likely because the AST was directly manipulated",
 
   modulesIllegalExportName: "Illegal export $1",
-  modulesDuplicateDeclarations: "Duplicate module declarations with the same source but in different scopes",
+  modulesDuplicateDeclarations:
+    "Duplicate module declarations with the same source but in different scopes",
 
   undeclaredVariable: "Reference to undeclared variable $1",
-  undeclaredVariableType: "Referencing a type alias outside of a type annotation",
+  undeclaredVariableType:
-  undeclaredVariableSuggestion: "Reference to undeclared variable $1 - did you mean $2?",
+    "Referencing a type alias outside of a type annotation",
+  undeclaredVariableSuggestion:
+    "Reference to undeclared variable $1 - did you mean $2?",
 
-  traverseNeedsParent: "You must pass a scope and parentPath unless traversing a Program/File. Instead of that you tried to traverse a $1 node without passing scope and parentPath.",
+  traverseNeedsParent:
-  traverseVerifyRootFunction: "You passed `traverse()` a function when it expected a visitor object, are you sure you didn't mean `{ enter: Function }`?",
+    "You must pass a scope and parentPath unless traversing a Program/File. Instead of that you tried to traverse a $1 node without passing scope and parentPath.",
-  traverseVerifyVisitorProperty: "You passed `traverse()` a visitor object with the property $1 that has the invalid property $2",
+  traverseVerifyRootFunction:
-  traverseVerifyNodeType: "You gave us a visitor for the node type $1 but it's not a valid type",
+    "You passed `traverse()` a function when it expected a visitor object, are you sure you didn't mean `{ enter: Function }`?",
+  traverseVerifyVisitorProperty:
+    "You passed `traverse()` a visitor object with the property $1 that has the invalid property $2",
+  traverseVerifyNodeType:
+    "You gave us a visitor for the node type $1 but it's not a valid type",
 
-  pluginNotObject: "Plugin $2 specified in $1 was expected to return an object when invoked but returned $3",
+  pluginNotObject:
-  pluginNotFunction: "Plugin $2 specified in $1 was expected to return a function but returned $3",
+    "Plugin $2 specified in $1 was expected to return an object when invoked but returned $3",
-  pluginUnknown: "Unknown plugin $1 specified in $2 at $3, attempted to resolve relative to $4",
+  pluginNotFunction:
+    "Plugin $2 specified in $1 was expected to return a function but returned $3",
+  pluginUnknown:
+    "Unknown plugin $1 specified in $2 at $3, attempted to resolve relative to $4",
   pluginInvalidProperty: "Plugin $1 provided an invalid property of $2",
 };
 
@@ -55,7 +72,7 @@ export function get(key: string, ...args: Array<any>): string {
   args = parseArgs(args);
 
   // replace $0 placeholders with args
-  return msg.replace(/\$(\d+)/g, function (str, i) {
+  return msg.replace(/\$(\d+)/g, function(str, i) {
     return args[i - 1];
   });
 }
@@ -65,7 +82,7 @@ export function get(key: string, ...args: Array<any>): string {
  */
 
 export function parseArgs(args: Array<any>): Array<string> {
-  return args.map(function (val) {
+  return args.map(function(val) {
     if (val != null && val.inspect) {
       return val.inspect();
     } else {

packages/babel-plugin-check-es2015-constants/src/index.js

@@ -1,4 +1,4 @@
-export default function ({ messages }) {
+export default function({ messages }) {
   return {
     visitor: {
       Scope({ scope }) {

packages/babel-plugin-external-helpers/src/index.js

@@ -1,4 +1,4 @@
-export default function ({ types: t }) {
+export default function({ types: t }) {
   return {
     pre(file) {
       file.set("helpersNamespace", t.identifier("babelHelpers"));

packages/babel-plugin-syntax-async-functions/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("asyncFunctions");

packages/babel-plugin-syntax-async-generators/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("asyncGenerators");

packages/babel-plugin-syntax-class-properties/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("classProperties");

packages/babel-plugin-syntax-decorators/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("decorators");

packages/babel-plugin-syntax-do-expressions/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("doExpressions");

packages/babel-plugin-syntax-dynamic-import/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("dynamicImport");

packages/babel-plugin-syntax-exponentiation-operator/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("exponentiationOperator");

packages/babel-plugin-syntax-export-extensions/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("exportExtensions");

packages/babel-plugin-syntax-flow/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("flow");

packages/babel-plugin-syntax-function-bind/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("functionBind");

packages/babel-plugin-syntax-function-sent/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("functionSent");

packages/babel-plugin-syntax-jsx/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("jsx");

packages/babel-plugin-syntax-numeric-separator/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("numericSeparator");

packages/babel-plugin-syntax-object-rest-spread/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("objectRestSpread");

packages/babel-plugin-syntax-optional-chaining/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("optionalChaining");

packages/babel-plugin-syntax-trailing-function-commas/src/index.js

@@ -1,4 +1,4 @@
-export default function () {
+export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
       parserOpts.plugins.push("trailingFunctionCommas");

packages/babel-plugin-transform-async-functions/src/index.js

@@ -1,6 +1,6 @@
 import asyncSyntaxPlugin from "babel-plugin-syntax-async-functions";
 
-export default function () {
+export default function() {
   return {
     inherits: asyncSyntaxPlugin,
   };

packages/babel-plugin-transform-async-generator-functions/src/index.js

@@ -1,7 +1,7 @@
 import remapAsyncToGenerator from "babel-helper-remap-async-to-generator";
 import syntaxAsyncGenerators from "babel-plugin-syntax-async-generators";
 
-export default function ({ types: t }) {
+export default function({ types: t }) {
   const yieldStarVisitor = {
     Function(path) {
       path.skip();
@@ -12,7 +12,10 @@ export default function ({ types: t }) {
       const callee = state.addHelper("asyncGeneratorDelegate");
       node.argument = t.callExpression(callee, [
         t.callExpression(state.addHelper("asyncIterator"), [node.argument]),
-        t.memberExpression(state.addHelper("asyncGenerator"), t.identifier("await")),
+        t.memberExpression(
+          state.addHelper("asyncGenerator"),
+          t.identifier("await"),
+        ),
       ]);
     },
   };
@@ -27,9 +30,13 @@ export default function ({ types: t }) {
 
         remapAsyncToGenerator(path, state.file, {
           wrapAsync: t.memberExpression(
-            state.addHelper("asyncGenerator"), t.identifier("wrap")),
+            state.addHelper("asyncGenerator"),
+            t.identifier("wrap"),
+          ),
           wrapAwait: t.memberExpression(
-            state.addHelper("asyncGenerator"), t.identifier("await")),
+            state.addHelper("asyncGenerator"),
+            t.identifier("await"),
+          ),
         });
       },
     },

packages/babel-plugin-transform-async-to-generator/src/index.js

@@ -1,7 +1,7 @@
 import remapAsyncToGenerator from "babel-helper-remap-async-to-generator";
 import syntaxAsyncFunctions from "babel-plugin-syntax-async-functions";
 
-export default function () {
+export default function() {
   return {
     inherits: syntaxAsyncFunctions,
 

packages/babel-plugin-transform-async-to-module-method/src/index.js

@@ -1,7 +1,7 @@
 import remapAsyncToGenerator from "babel-helper-remap-async-to-generator";
 import syntaxAsyncFunctions from "babel-plugin-syntax-async-functions";
 
-export default function () {
+export default function() {
   return {
     inherits: syntaxAsyncFunctions,
 

packages/babel-plugin-transform-class-properties/src/index.js

@@ -2,7 +2,7 @@ import nameFunction from "babel-helper-function-name";
 import template from "babel-template";
 import syntaxClassProperties from "babel-plugin-syntax-class-properties";
 
-export default function ({ types: t }) {
+export default function({ types: t }) {
   const findBareSupers = {
     Super(path) {
       if (path.parentPath.isCallExpression({ callee: path.node })) {
@@ -29,14 +29,20 @@ export default function ({ types: t }) {
     });
   `);
 
-  const buildClassPropertySpec = (ref, { key, value, computed }) => buildObjectDefineProperty({
+  const buildClassPropertySpec = (ref, { key, value, computed }) =>
+    buildObjectDefineProperty({
       REF: ref,
-    KEY: (t.isIdentifier(key) && !computed) ? t.stringLiteral(key.name) : key,
+      KEY: t.isIdentifier(key) && !computed ? t.stringLiteral(key.name) : key,
       VALUE: value ? value : t.identifier("undefined"),
     });
 
-  const buildClassPropertyNonSpec = (ref, { key, value, computed }) => t.expressionStatement(
+  const buildClassPropertyNonSpec = (ref, { key, value, computed }) =>
-    t.assignmentExpression("=", t.memberExpression(ref, key, computed || t.isLiteral(key)), value)
+    t.expressionStatement(
+      t.assignmentExpression(
+        "=",
+        t.memberExpression(ref, key, computed || t.isLiteral(key)),
+        value,
+      ),
     );
 
   return {
@@ -44,8 +50,9 @@ export default function ({ types: t }) {
 
     visitor: {
       Class(path, state) {
-        const buildClassProperty = state.opts.spec ? buildClassPropertySpec :
+        const buildClassProperty = state.opts.spec
-          buildClassPropertyNonSpec;
+          ? buildClassPropertySpec
+          : buildClassPropertyNonSpec;
         const isDerived = !!path.node.superClass;
         let constructor;
         const props = [];
@@ -67,7 +74,8 @@ export default function ({ types: t }) {
         if (path.isClassExpression() || !path.node.id) {
           nameFunction(path);
           ref = path.scope.generateUidIdentifier("class");
-        } else { // path.isClassDeclaration() && path.node.id
+        } else {
+          // path.isClassDeclaration() && path.node.id
           ref = path.node.id;
         }
 
@@ -93,17 +101,20 @@ export default function ({ types: t }) {
 
         if (instanceBody.length) {
           if (!constructor) {
-            const newConstructor = t.classMethod("constructor", t.identifier("constructor"), [],
+            const newConstructor = t.classMethod(
-              t.blockStatement([]));
+              "constructor",
+              t.identifier("constructor"),
+              [],
+              t.blockStatement([]),
+            );
             if (isDerived) {
               newConstructor.params = [t.restElement(t.identifier("args"))];
               newConstructor.body.body.push(
                 t.returnStatement(
-                  t.callExpression(
+                  t.callExpression(t.super(), [
-                    t.super(),
+                    t.spreadElement(t.identifier("args")),
-                    [t.spreadElement(t.identifier("args"))]
+                  ]),
-                  )
+                ),
-                )
               );
             }
             [constructor] = body.unshiftContainer("body", newConstructor);
@@ -120,19 +131,29 @@ export default function ({ types: t }) {
           }
 
           if (collisionState.collision) {
-            const initialisePropsRef = path.scope.generateUidIdentifier("initialiseProps");
+            const initialisePropsRef = path.scope.generateUidIdentifier(
+              "initialiseProps",
+            );
 
-            nodes.push(t.variableDeclaration("var", [
+            nodes.push(
+              t.variableDeclaration("var", [
                 t.variableDeclarator(
                   initialisePropsRef,
-                t.functionExpression(null, [], t.blockStatement(instanceBody))
+                  t.functionExpression(
+                    null,
+                    [],
+                    t.blockStatement(instanceBody),
                   ),
-            ]));
+                ),
+              ]),
+            );
 
             instanceBody = [
               t.expressionStatement(
-                t.callExpression(t.memberExpression(initialisePropsRef, t.identifier("call")), [
+                t.callExpression(
-                  t.thisExpression()])
+                  t.memberExpression(initialisePropsRef, t.identifier("call")),
+                  [t.thisExpression()],
+                ),
               ),
             ];
           }
@@ -159,7 +180,8 @@ export default function ({ types: t }) {
         if (path.isClassExpression()) {
           path.scope.push({ id: ref });
           path.replaceWith(t.assignmentExpression("=", ref, path.node));
-        } else { // path.isClassDeclaration()
+        } else {
+          // path.isClassDeclaration()
           if (!path.node.id) {
             path.node.id = ref;
           }
@@ -177,7 +199,7 @@ export default function ({ types: t }) {
 
         const body = classExp.get("body");
         const members = body.get("body");
-        if (members.some((member) => member.isClassProperty())) {
+        if (members.some(member => member.isClassProperty())) {
           path.ensureBlock();
         }
       },

packages/babel-plugin-transform-decorators/src/index.js

@@ -15,7 +15,6 @@ const buildGetDescriptor = template(`
     Object.getOwnPropertyDescriptor(TARGET, PROPERTY);
 `);
 
-
 const buildGetObjectInitializer = template(`
     (TEMP = Object.getOwnPropertyDescriptor(TARGET, PROPERTY), (TEMP = TEMP ? TEMP.value : undefined), {
         enumerable: true,
@@ -88,7 +87,9 @@ export default function({ types: t }) {
    */
   function ensureApplyDecoratedDescriptorHelper(path, state) {
     if (!state.applyDecoratedDescriptor) {
-      state.applyDecoratedDescriptor = path.scope.generateUidIdentifier("applyDecoratedDescriptor");
+      state.applyDecoratedDescriptor = path.scope.generateUidIdentifier(
+        "applyDecoratedDescriptor",
+      );
       const helper = buildApplyDecoratedDescriptor({
         NAME: state.applyDecoratedDescriptor,
       });
@@ -103,7 +104,9 @@ export default function({ types: t }) {
    */
   function ensureInitializerDefineProp(path, state) {
     if (!state.initializerDefineProp) {
-      state.initializerDefineProp = path.scope.generateUidIdentifier("initDefineProp");
+      state.initializerDefineProp = path.scope.generateUidIdentifier(
+        "initDefineProp",
+      );
       const helper = buildInitializerDefineProperty({
         NAME: state.initializerDefineProp,
       });
@@ -119,7 +122,9 @@ export default function({ types: t }) {
    */
   function ensureInitializerWarning(path, state) {
     if (!state.initializerWarningHelper) {
-      state.initializerWarningHelper = path.scope.generateUidIdentifier("initializerWarningHelper");
+      state.initializerWarningHelper = path.scope.generateUidIdentifier(
+        "initializerWarningHelper",
+      );
       const helper = buildInitializerWarningHelper({
         NAME: state.initializerWarningHelper,
       });
@@ -135,20 +140,29 @@ export default function({ types: t }) {
    */
   function applyEnsureOrdering(path) {
     // TODO: This should probably also hoist computed properties.
-    const decorators = (
+    const decorators = (path.isClass()
-      path.isClass()
       ? [path].concat(path.get("body.body"))
-      : path.get("properties")
+      : path.get("properties")).reduce(
-    ).reduce((acc, prop) => acc.concat(prop.node.decorators || []), []);
+      (acc, prop) => acc.concat(prop.node.decorators || []),
+      [],
+    );
 
-    const identDecorators = decorators.filter((decorator) => !t.isIdentifier(decorator.expression));
+    const identDecorators = decorators.filter(
+      decorator => !t.isIdentifier(decorator.expression),
+    );
     if (identDecorators.length === 0) return;
 
-    return t.sequenceExpression(identDecorators.map((decorator) => {
+    return t.sequenceExpression(
+      identDecorators
+        .map(decorator => {
           const expression = decorator.expression;
-      const id = decorator.expression = path.scope.generateDeclaredUidIdentifier("dec");
+          const id = (decorator.expression = path.scope.generateDeclaredUidIdentifier(
+            "dec",
+          ));
           return t.assignmentExpression("=", id, expression);
-    }).concat([path.node]));
+        })
+        .concat([path.node]),
+    );
   }
 
   /**
@@ -164,7 +178,7 @@ export default function({ types: t }) {
     const name = classPath.scope.generateDeclaredUidIdentifier("class");
 
     return decorators
-            .map((dec) => dec.expression)
+      .map(dec => dec.expression)
       .reverse()
       .reduce(function(acc, decorator) {
         return buildClassDecorator({
@@ -207,7 +221,9 @@ export default function({ types: t }) {
    * A helper to pull out property decorators into a sequence expression.
    */
   function applyTargetDecorators(path, state, decoratedProps) {
-    const name = path.scope.generateDeclaredUidIdentifier(path.isClass() ? "class" : "obj");
+    const name = path.scope.generateDeclaredUidIdentifier(
+      path.isClass() ? "class" : "obj",
+    );
 
     const exprs = decoratedProps.reduce(function(acc, node) {
       const decorators = node.decorators || [];
@@ -216,36 +232,58 @@ export default function({ types: t }) {
       if (decorators.length === 0) return acc;
 
       if (node.computed) {
-        throw path.buildCodeFrameError("Computed method/property decorators are not yet supported.");
+        throw path.buildCodeFrameError(
+          "Computed method/property decorators are not yet supported.",
+        );
       }
 
-      const property = t.isLiteral(node.key) ? node.key : t.stringLiteral(node.key.name);
+      const property = t.isLiteral(node.key)
+        ? node.key
+        : t.stringLiteral(node.key.name);
 
-      const target = (path.isClass() && !node.static) ? buildClassPrototype({
+      const target =
+        path.isClass() && !node.static
+          ? buildClassPrototype({
               CLASS_REF: name,
-      }).expression : name;
+            }).expression
+          : name;
 
       if (t.isClassProperty(node, { static: false })) {
-        const descriptor = path.scope.generateDeclaredUidIdentifier("descriptor");
+        const descriptor = path.scope.generateDeclaredUidIdentifier(
-
+          "descriptor",
-        const initializer = node.value ?
-                        t.functionExpression(null, [], t.blockStatement([t.returnStatement(node.value)])) :
-                        t.nullLiteral();
-        node.value = t.callExpression(
-          ensureInitializerWarning(path, state), [descriptor, t.thisExpression()]
         );
 
+        const initializer = node.value
+          ? t.functionExpression(
+              null,
+              [],
+              t.blockStatement([t.returnStatement(node.value)]),
+            )
+          : t.nullLiteral();
+        node.value = t.callExpression(ensureInitializerWarning(path, state), [
+          descriptor,
+          t.thisExpression(),
+        ]);
+
         acc = acc.concat([
           t.assignmentExpression(
-            "=", descriptor, t.callExpression(ensureApplyDecoratedDescriptorHelper(path, state), [
+            "=",
+            descriptor,
+            t.callExpression(
+              ensureApplyDecoratedDescriptorHelper(path, state),
+              [
                 target,
                 property,
-              t.arrayExpression(decorators.map((dec) => dec.expression)),
+                t.arrayExpression(decorators.map(dec => dec.expression)),
                 t.objectExpression([
-                t.objectProperty(t.identifier("enumerable"), t.booleanLiteral(true)),
+                  t.objectProperty(
+                    t.identifier("enumerable"),
+                    t.booleanLiteral(true),
+                  ),
                   t.objectProperty(t.identifier("initializer"), initializer),
                 ]),
-            ])
+              ],
+            ),
           ),
         ]);
       } else {
@@ -253,21 +291,20 @@ export default function({ types: t }) {
           t.callExpression(ensureApplyDecoratedDescriptorHelper(path, state), [
             target,
             property,
-              t.arrayExpression(decorators.map((dec) => dec.expression)),
+            t.arrayExpression(decorators.map(dec => dec.expression)),
-              (
             t.isObjectProperty(node) ||
-                t.isClassProperty(node, { static: true })) ?
+            t.isClassProperty(node, { static: true })
-                buildGetObjectInitializer({
+              ? buildGetObjectInitializer({
                   TEMP: path.scope.generateDeclaredUidIdentifier("init"),
                   TARGET: target,
                   PROPERTY: property,
-                }).expression : buildGetDescriptor({
+                }).expression
+              : buildGetDescriptor({
                   TARGET: target,
                   PROPERTY: property,
-                }
+                }).expression,
-              ).expression,
             target,
-            ])
+          ]),
         );
       }
 
@@ -289,35 +326,42 @@ export default function({ types: t }) {
         if (!path.get("declaration").isClassDeclaration()) return;
 
         const { node } = path;
-        const ref = node.declaration.id || path.scope.generateUidIdentifier("default");
+        const ref =
+          node.declaration.id || path.scope.generateUidIdentifier("default");
         node.declaration.id = ref;
 
         // Split the class declaration and the export into two separate statements.
         path.replaceWith(node.declaration);
-        path.insertAfter(t.exportNamedDeclaration(null, [t.exportSpecifier(ref, t.identifier("default"))]));
+        path.insertAfter(
+          t.exportNamedDeclaration(null, [
+            t.exportSpecifier(ref, t.identifier("default")),
+          ]),
+        );
       },
       ClassDeclaration(path) {
         const { node } = path;
 
         const ref = node.id || path.scope.generateUidIdentifier("class");
 
-        path.replaceWith(t.variableDeclaration("let", [
+        path.replaceWith(
+          t.variableDeclaration("let", [
             t.variableDeclarator(ref, t.toExpression(node)),
-        ]));
+          ]),
+        );
       },
       ClassExpression(path, state) {
         // Create a replacement for the class node if there is one. We do one pass to replace classes with
         // class decorators, and a second pass to process method decorators.
-        const decoratedClass = (
+        const decoratedClass =
           applyEnsureOrdering(path) ||
           applyClassDecorators(path, state) ||
-          applyMethodDecorators(path, state)
+          applyMethodDecorators(path, state);
-        );
 
         if (decoratedClass) path.replaceWith(decoratedClass);
       },
       ObjectExpression(path, state) {
-        const decoratedObject = applyEnsureOrdering(path) || applyObjectDecorators(path, state);
+        const decoratedObject =
+          applyEnsureOrdering(path) || applyObjectDecorators(path, state);
 
         if (decoratedObject) path.replaceWith(decoratedObject);
       },
@@ -328,14 +372,22 @@ export default function({ types: t }) {
         if (!path.get("left").isMemberExpression()) return;
         if (!path.get("left.property").isIdentifier()) return;
         if (!path.get("right").isCallExpression()) return;
-        if (!path.get("right.callee").isIdentifier({ name: state.initializerWarningHelper.name })) return;
+        if (
+          !path
+            .get("right.callee")
+            .isIdentifier({ name: state.initializerWarningHelper.name })
+        ) {
+          return;
+        }
 
-        path.replaceWith(t.callExpression(ensureInitializerDefineProp(path, state), [
+        path.replaceWith(
+          t.callExpression(ensureInitializerDefineProp(path, state), [
             path.get("left.object").node,
             t.stringLiteral(path.get("left.property").node.name),
             path.get("right.arguments")[0].node,
             path.get("right.arguments")[1].node,
-        ]));
+          ]),
+        );
       },
     },
   };

packages/babel-plugin-transform-do-expressions/src/index.js

@@ -1,6 +1,6 @@
 import syntaxDoExpressions from "babel-plugin-syntax-do-expressions";
 
-export default function () {
+export default function() {
   return {
     inherits: syntaxDoExpressions,
 

packages/babel-plugin-transform-es2015-arrow-functions/src/index.js

@@ -2,10 +2,13 @@
 
 import type NodePath from "babel-traverse";
 
-export default function () {
+export default function() {
   return {
     visitor: {
-      ArrowFunctionExpression(path: NodePath<BabelNodeArrowFunctionExpression>, state: Object) {
+      ArrowFunctionExpression(
+        path: NodePath<BabelNodeArrowFunctionExpression>,
+        state: Object,
+      ) {
         // In some conversion cases, it may have already been converted to a function while this callback
         // was queued up.
         if (!path.isArrowFunctionExpression()) return;

packages/babel-plugin-transform-es2015-block-scoped-functions/src/index.js

@@ -1,4 +1,4 @@
-export default function ({ types: t }) {
+export default function({ types: t }) {
   function statementList(key, path) {
     const paths: Array = path.get(key);
 
@@ -24,7 +24,10 @@ export default function ({ types: t }) {
     visitor: {
       BlockStatement(path) {
         const { node, parent } = path;
-        if (t.isFunction(parent, { body: node }) || t.isExportDeclaration(parent)) {
+        if (
+          t.isFunction(parent, { body: node }) ||
+          t.isExportDeclaration(parent)
+        ) {
           return;
         }
 

packages/babel-plugin-transform-es2015-block-scoping/src/index.js

@@ -8,7 +8,7 @@ import values from "lodash/values";
 import extend from "lodash/extend";
 import template from "babel-template";
 
-export default function () {
+export default function() {
   return {
     visitor: {
       VariableDeclaration(path, file) {
@@ -44,20 +44,38 @@ export default function () {
       Loop(path, file) {
         const { node, parent, scope } = path;
         t.ensureBlock(node);
-        const blockScoping = new BlockScoping(path, path.get("body"), parent, scope, file);
+        const blockScoping = new BlockScoping(
+          path,
+          path.get("body"),
+          parent,
+          scope,
+          file,
+        );
         const replace = blockScoping.run();
         if (replace) path.replaceWith(replace);
       },
 
       CatchClause(path, file) {
         const { parent, scope } = path;
-        const blockScoping = new BlockScoping(null, path.get("body"), parent, scope, file);
+        const blockScoping = new BlockScoping(
+          null,
+          path.get("body"),
+          parent,
+          scope,
+          file,
+        );
         blockScoping.run();
       },
 
       "BlockStatement|SwitchStatement|Program"(path, file) {
         if (!ignoreBlock(path)) {
-          const blockScoping = new BlockScoping(null, path, path.parent, path.scope, file);
+          const blockScoping = new BlockScoping(
+            null,
+            path,
+            path.parent,
+            path.scope,
+            file,
+          );
           blockScoping.run();
         }
       },
@@ -80,7 +98,13 @@ function isBlockScoped(node) {
   return true;
 }
 
-function convertBlockScopedToVar(path, node, parent, scope, moveBindingsToParent = false) {
+function convertBlockScopedToVar(
+  path,
+  node,
+  parent,
+  scope,
+  moveBindingsToParent = false,
+) {
   if (!node) {
     node = path.node;
   }
@@ -111,7 +135,8 @@ function isVar(node) {
   return t.isVariableDeclaration(node, { kind: "var" }) && !isBlockScoped(node);
 }
 
-const letReferenceBlockVisitor = traverse.visitors.merge([{
+const letReferenceBlockVisitor = traverse.visitors.merge([
+  {
     Loop: {
       enter(path, state) {
         state.loopDepth++;
@@ -129,9 +154,12 @@ const letReferenceBlockVisitor = traverse.visitors.merge([{
       }
       return path.skip();
     },
-}, tdzVisitor]);
+  },
+  tdzVisitor,
+]);
 
-const letReferenceFunctionVisitor = traverse.visitors.merge([{
+const letReferenceFunctionVisitor = traverse.visitors.merge([
+  {
     ReferencedIdentifier(path, state) {
       const ref = state.letReferences[path.node.name];
 
@@ -145,7 +173,9 @@ const letReferenceFunctionVisitor = traverse.visitors.merge([{
 
       state.closurify = true;
     },
-}, tdzVisitor]);
+  },
+  tdzVisitor,
+]);
 
 const hoistVarDeclarationsVisitor = {
   enter(path, self) {
@@ -166,7 +196,9 @@ const hoistVarDeclarationsVisitor = {
         node.left = node.left.declarations[0].id;
       }
     } else if (isVar(node, parent)) {
-      path.replaceWithMultiple(self.pushDeclar(node).map((expr) => t.expressionStatement(expr)));
+      path.replaceWithMultiple(
+        self.pushDeclar(node).map(expr => t.expressionStatement(expr)),
+      );
     } else if (path.isFunction()) {
       return path.skip();
     }
@@ -184,7 +216,12 @@ const continuationVisitor = {
     if (path.isAssignmentExpression() || path.isUpdateExpression()) {
       const bindings = path.getBindingIdentifiers();
       for (const name in bindings) {
-        if (state.outsideReferences[name] !== path.scope.getBindingIdentifier(name)) continue;
+        if (
+          state.outsideReferences[name] !==
+          path.scope.getBindingIdentifier(name)
+        ) {
+          continue;
+        }
         state.reassignments[name] = true;
       }
     }
@@ -252,7 +289,10 @@ const loopVisitor = {
     if (path.isReturnStatement()) {
       state.hasReturn = true;
       replace = t.objectExpression([
-        t.objectProperty(t.identifier("v"), node.argument || scope.buildUndefinedNode()),
+        t.objectProperty(
+          t.identifier("v"),
+          node.argument || scope.buildUndefinedNode(),
+        ),
       ]);
     }
 
@@ -266,7 +306,13 @@ const loopVisitor = {
 };
 
 class BlockScoping {
-  constructor(loopPath?: NodePath, blockPath: NodePath, parent: Object, scope: Scope, file: File) {
+  constructor(
+    loopPath?: NodePath,
+    blockPath: NodePath,
+    parent: Object,
+    scope: Scope,
+    file: File,
+  ) {
     this.parent = parent;
     this.scope = scope;
     this.file = file;
@@ -281,7 +327,8 @@ class BlockScoping {
 
     if (loopPath) {
       this.loopParent = loopPath.parent;
-      this.loopLabel = t.isLabeledStatement(this.loopParent) && this.loopParent.label;
+      this.loopLabel =
+        t.isLabeledStatement(this.loopParent) && this.loopParent.label;
       this.loopPath = loopPath;
       this.loop = loopPath.node;
     }
@@ -360,11 +407,13 @@ class BlockScoping {
         // The same identifier might have been bound separately in the block scope and
         // the enclosing scope (e.g. loop or catch statement), so we should handle both
         // individually
-        if (scope.hasOwnBinding(key))
+        if (scope.hasOwnBinding(key)) {
-          {scope.rename(ref.name);}
+          scope.rename(ref.name);
+        }
 
-        if (this.blockPath.scope.hasOwnBinding(key))
+        if (this.blockPath.scope.hasOwnBinding(key)) {
-          {this.blockPath.scope.rename(ref.name);}
+          this.blockPath.scope.rename(ref.name);
+        }
       }
     }
   }
@@ -373,7 +422,7 @@ class BlockScoping {
     if (this.file.opts.throwIfClosureRequired) {
       throw this.blockPath.buildCodeFrameError(
         "Compiling let/const in this block would add a closure " +
-        "(throwIfClosureRequired)."
+          "(throwIfClosureRequired).",
       );
     }
     const block = this.block;
@@ -385,7 +434,10 @@ class BlockScoping {
       for (const name in outsideRefs) {
         const id = outsideRefs[name];
 
-        if (this.scope.hasGlobal(id.name) || this.scope.parentHasBinding(id.name)) {
+        if (
+          this.scope.hasGlobal(id.name) ||
+          this.scope.parentHasBinding(id.name)
+        ) {
           delete outsideRefs[id.name];
           delete this.letReferences[id.name];
 
@@ -411,8 +463,11 @@ class BlockScoping {
     const isSwitch = this.blockPath.isSwitchStatement();
 
     // build the closure that we're going to wrap the block with, possible wrapping switch(){}
-    const fn = t.functionExpression(null, params,
+    const fn = t.functionExpression(
-      t.blockStatement(isSwitch ? [block] : block.body));
+      null,
+      params,
+      t.blockStatement(isSwitch ? [block] : block.body),
+    );
 
     // continuation
     this.addContinuations(fn);
@@ -421,7 +476,12 @@ class BlockScoping {
     let basePath = ".callee";
 
     // handle generators
-    const hasYield = traverse.hasType(fn.body, this.scope, "YieldExpression", t.FUNCTION_TYPES);
+    const hasYield = traverse.hasType(
+      fn.body,
+      this.scope,
+      "YieldExpression",
+      t.FUNCTION_TYPES,
+    );
     if (hasYield) {
       fn.generator = true;
       call = t.yieldExpression(call, true);
@@ -429,7 +489,12 @@ class BlockScoping {
     }
 
     // handlers async functions
-    const hasAsync = traverse.hasType(fn.body, this.scope, "AwaitExpression", t.FUNCTION_TYPES);
+    const hasAsync = traverse.hasType(
+      fn.body,
+      this.scope,
+      "AwaitExpression",
+      t.FUNCTION_TYPES,
+    );
     if (hasAsync) {
       fn.async = true;
       call = t.awaitExpression(call);
@@ -441,9 +506,9 @@ class BlockScoping {
     if (this.has.hasReturn || this.has.hasBreakContinue) {
       const ret = this.scope.generateUidIdentifier("ret");
 
-      this.body.push(t.variableDeclaration("var", [
+      this.body.push(
-        t.variableDeclarator(ret, call),
+        t.variableDeclaration("var", [t.variableDeclarator(ret, call)]),
-      ]));
+      );
       placeholderPath = "declarations.0.init" + basePath;
       index = this.body.length - 1;
 
@@ -471,9 +536,9 @@ class BlockScoping {
     let fnPath;
     if (this.loop) {
       const ref = this.scope.generateUidIdentifier("loop");
-      const p = this.loopPath.insertBefore(t.variableDeclaration("var", [
+      const p = this.loopPath.insertBefore(
-        t.variableDeclarator(ref, fn),
+        t.variableDeclaration("var", [t.variableDeclarator(ref, fn)]),
-      ]));
+      );
 
       placeholder.replaceWith(ref);
       fnPath = p[0].get("declarations.0.init");
@@ -512,7 +577,9 @@ class BlockScoping {
       this.scope.rename(param.name, newParam.name, fn);
 
       // assign outer reference as it's been modified internally and needs to be retained
-      fn.body.body.push(t.expressionStatement(t.assignmentExpression("=", param, newParam)));
+      fn.body.body.push(
+        t.expressionStatement(t.assignmentExpression("=", param, newParam)),
+      );
     }
   }
 
@@ -531,7 +598,11 @@ class BlockScoping {
 
     const addDeclarationsFromChild = (path, node) => {
       node = node || path.node;
-      if (t.isClassDeclaration(node) || t.isFunctionDeclaration(node) || isBlockScoped(node)) {
+      if (
+        t.isClassDeclaration(node) ||
+        t.isFunctionDeclaration(node) ||
+        isBlockScoped(node)
+      ) {
         if (isBlockScoped(node)) {
           convertBlockScopedToVar(path, node, block, this.scope);
         }
@@ -585,7 +656,7 @@ class BlockScoping {
     };
 
     const loopOrFunctionParent = this.blockPath.find(
-      (path) => path.isLoop() || path.isFunction()
+      path => path.isLoop() || path.isFunction(),
     );
     if (loopOrFunctionParent && loopOrFunctionParent.isLoop()) {
       // There is a loop ancestor closer than the closest function, so we
@@ -686,18 +757,20 @@ class BlockScoping {
 
       if (cases.length === 1) {
         const single = cases[0];
-        body.push(t.ifStatement(
+        body.push(
+          t.ifStatement(
             t.binaryExpression("===", ret, single.test),
-          single.consequent[0]
+            single.consequent[0],
-        ));
+          ),
+        );
       } else {
         if (this.loop) {
           // https://github.com/babel/babel/issues/998
           for (let i = 0; i < cases.length; i++) {
             const caseConsequent = cases[i].consequent[0];
             if (t.isBreakStatement(caseConsequent) && !caseConsequent.label) {
-              caseConsequent.label = this.loopLabel = this.loopLabel ||
+              caseConsequent.label = this.loopLabel =
-                this.scope.generateUidIdentifier("loop");
+                this.loopLabel || this.scope.generateUidIdentifier("loop");
             }
           }
         }

packages/babel-plugin-transform-es2015-block-scoping/src/tdz.js

@@ -13,10 +13,11 @@ function getTDZStatus(refPath, bindingPath) {
 }
 
 function buildTDZAssert(node, file) {
-  return t.callExpression(
+  return t.callExpression(file.addHelper("temporalRef"), [
-    file.addHelper("temporalRef"),
+    node,
-    [node, t.stringLiteral(node.name), file.addHelper("temporalUndefined")]
+    t.stringLiteral(node.name),
-  );
+    file.addHelper("temporalUndefined"),
+  ]);
 }
 
 function isReference(node, scope, state) {
@@ -56,12 +57,18 @@ export const visitor = {
         path.replaceWith(assert);
       }
     } else if (status === "outside") {
-      path.replaceWith(t.throwStatement(t.inherits(
+      path.replaceWith(
+        t.throwStatement(
+          t.inherits(
             t.newExpression(t.identifier("ReferenceError"), [
-          t.stringLiteral(`${node.name} is not defined - temporal dead zone`),
+              t.stringLiteral(
+                `${node.name} is not defined - temporal dead zone`,
+              ),
             ]),
-        node
+            node,
-      )));
+          ),
+        ),
+      );
     }
   },
 

packages/babel-plugin-transform-es2015-classes/src/index.js

@@ -2,7 +2,7 @@ import LooseTransformer from "./loose";
 import VanillaTransformer from "./vanilla";
 import nameFunction from "babel-helper-function-name";
 
-export default function ({ types: t }) {
+export default function({ types: t }) {
   // todo: investigate traversal requeueing
   const VISITED = Symbol();
 
@@ -12,15 +12,17 @@ export default function ({ types: t }) {
         if (!path.get("declaration").isClassDeclaration()) return;
 
         const { node } = path;
-        const ref = node.declaration.id || path.scope.generateUidIdentifier("class");
+        const ref =
+          node.declaration.id || path.scope.generateUidIdentifier("class");
         node.declaration.id = ref;
 
         // Split the class declaration and the export into two separate statements.
         path.replaceWith(node.declaration);
-        path.insertAfter(t.exportNamedDeclaration(
+        path.insertAfter(
-          null,
+          t.exportNamedDeclaration(null, [
-          [t.exportSpecifier(ref, t.identifier("default"))]
+            t.exportSpecifier(ref, t.identifier("default")),
-        ));
+          ]),
+        );
       },
 
       ClassDeclaration(path) {
@@ -28,9 +30,11 @@ export default function ({ types: t }) {
 
         const ref = node.id || path.scope.generateUidIdentifier("class");
 
-        path.replaceWith(t.variableDeclaration("let", [
+        path.replaceWith(
+          t.variableDeclaration("let", [
             t.variableDeclarator(ref, t.toExpression(node)),
-        ]));
+          ]),
+        );
       },
 
       ClassExpression(path, state) {
@@ -47,7 +51,10 @@ export default function ({ types: t }) {
 
         path.replaceWith(new Constructor(path, state.file).run());
 
-        if (path.isCallExpression() && path.get("callee").isArrowFunctionExpression()) {
+        if (
+          path.isCallExpression() &&
+          path.get("callee").isArrowFunctionExpression()
+        ) {
           path.get("callee").arrowFunctionToExpression();
         }
       },