v3.3.12

Concatenate adjacent string literals in JSX

.jscsrc

@@ -14,7 +14,6 @@
   },
   "disallowSpacesInsideArrayBrackets": true,
   "disallowSpacesInsideParentheses": true,
-  "disallowQuotedKeysInObjects": true,
   "disallowSpaceAfterObjectKeys": true,
   "disallowSpaceAfterPrefixUnaryOperators": true,
   "disallowSpaceBeforePostfixUnaryOperators": true,
@@ -35,7 +34,6 @@
   "requireSpaceAfterBinaryOperators": true,
   "requireLineFeedAtFileEnd": true,
   "requireCapitalizedConstructors": true,
-  "requireDotNotation": true,
   "requireSpacesInForStatement": true,
   "requireCurlyBraces": [
     "do"
@@ -51,7 +49,8 @@
     "return",
     "try",
     "catch",
-    "typeof"
+    "typeof",
+    "function"
   ],
   "validateLineBreaks": "LF",
   "validateQuoteMarks": "\"",

CHANGELOG.md

@@ -11,6 +11,52 @@
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
+## 3.3.12
+
+ * **Bug Fix**
+  * Don't override `MemberExpression`s with `core-js` in `selfContaiend` if a local binding exists.
+
+## 3.3.11
+
+ * **Bug Fix**
+  * Fix the require cache.
+
+## 3.3.10
+
+ * **Internal**
+  * Restructure transformers so they're only ran if the AST contains nodes that they need to worry about. Improves transpilation speed significantly.
+ * **Bug Fix**
+  * Fix source maps not tracking end of node locations.
+ * **Spec Compliancy**
+  * Use static super references as the home object is actually done at definition time.
+ * **Polish**
+  * Force the `es6.destructuring` transformer to be whitelisted when the `es7.objectSpread` transformer is.
+  * Join sibling string literals when creating JSX.
+
+## 3.3.9
+
+ * **Bug Fix**
+  * Fix super inside of functions.
+  * Fix super constructor inheritance.
+
+## 3.3.7
+
+ * **Bug Fix**
+  * Add `--use-strict` to valid node flags in `6to5-node`.
+  * Fix booleans not being properly stripped from the arguments in `6to5-node`.
+  * Force `.js` extension when writing files to directories with `6to5`.
+
+## 3.3.5
+
+ * **Bug Fix**
+  * Fix block scoping inside of while loops.
+  * Make module name regex more conservative. Thanks [@johlrich](https://github.com/johlrich)!
+  * Fix block scoping of constants.
+  * Fix istanbul interop.
+  * Make JSX transforming more inline with the official transformer with spaces after non-empty last lines.
+ * **Polish**
+  * Make it illegal to export a property called `__esModule`.
+
 ## 3.3.4
 
  * **Polish**
@@ -333,8 +379,8 @@ _Note: Gaps between patch versions are faulty/broken releases._
  * **Polish**
   * Rest parameters now allocate the array before populating.
  * **Internal**
-  * `for...in` loops have been changed to optimised `for` loops - better performance and no enumeration of protoype keys.
-  * Parts of the code generator have now been optimised thanks to [gaearon](https://github.com/gaearon).
+  * `for...in` loops have been changed to optimized `for` loops - better performance and no enumeration of protoype keys.
+  * Parts of the code generator have now been optimized thanks to [gaearon](https://github.com/gaearon).
 
 ## 2.12.3
 
@@ -357,7 +403,7 @@ _Note: Gaps between patch versions are faulty/broken releases._
  * **Bug Fix**
   * Support non-string JSX literals.
  * **New Feature**
-  * Loose mode for some transformers that enables non-spec behaviour.
+  * Loose mode for some transformers that enables non-spec behavior.
  * **Internal**
   * Uglify `--mangle sort` has been added to the build script, cutting minified scripts in half.
 
@@ -795,7 +841,7 @@ _Note: Gaps between patch versions are faulty/broken releases._
 
 ## 1.13.2
 
- * Optimise `Array.from` usage by adding a helper method.
+ * Optimize `Array.from` usage by adding a helper method.
  * Upgrade `acorn-6to5`.
 
 ## 1.13.1

NOTES.md

@@ -1,3 +1,3 @@
 # Notes
 
- * Wildcard exports/imports wont normalise if `export default` is a non-object. See [#224](https://github.com/6to5/6to5/issues/224).
+ * Wildcard exports/imports wont normalize if `export default` is a non-object. See [#224](https://github.com/6to5/6to5/issues/224).

bin/6to5-minify

@@ -0,0 +1,7 @@
+#!/usr/bin/env node
+
+var opts = require("./6to5").opts;
+opts.optional = (opts.optional || []).concat("minification");
+opts.format = {
+  compact: true
+};

bin/6to5-node

@@ -35,6 +35,7 @@ process.argv.slice(2).forEach(function(arg){
     case "--prof":
     case "--throw-deprecation":
     case "--trace-deprecation":
+    case "--use-strict":
       args.unshift(arg);
       break;
 

bin/6to5/dir.js

@@ -11,6 +11,9 @@ module.exports = function (commander, filenames, opts) {
   }
 
   var write = function (src, relative) {
+    // remove extension and then append back on .js
+    relative = relative.replace(/\.(\w*?)$/, "") + ".js";
+
     var dest = path.join(commander.outDir, relative);
 
     var data = util.compile(src, { sourceMapName: dest });

bin/6to5/index.js

@@ -114,12 +114,17 @@ exports.opts = {
   loose:                  commander.loose
 };
 
-var fn;
+setTimeout(function () {
+  // this is just a hack to give `6to5-minify` and other files including this
+  // time to modify `exports.opts`
 
-if (commander.outDir) {
-  fn = require("./dir");
-} else {
-  fn = require("./file");
-}
+  var fn;
 
-fn(commander, filenames, exports.opts);
+  if (commander.outDir) {
+    fn = require("./dir");
+  } else {
+    fn = require("./file");
+  }
+
+  fn(commander, filenames, exports.opts);
+}, 0);

bin/_6to5-node

@@ -72,7 +72,8 @@ if (program.eval || program.print) {
       }
 
       if (arg[0] === "-") {
-        if (program[arg.slice(2)]) {
+        var parsedArg = program[arg.slice(2)];
+        if (parsedArg && parsedArg !== true) {
           ignoreNext = true;
         }
       } else {

lib/6to5/file.js

@@ -4,16 +4,17 @@ module.exports = File;
 
 var SHEBANG_REGEX = /^\#\!.*/;
 
+var isFunction = require("lodash/lang/isFunction");
 var transform  = require("./transformation");
 var generate   = require("./generation");
+var defaults   = require("lodash/object/defaults");
+var contains   = require("lodash/collection/contains");
 var clone      = require("./helpers/clone");
 var Scope      = require("./traverse/scope");
 var util       = require("./util");
-var t          = require("./types");
-var contains   = require("lodash/collection/contains");
+var path       = require("path");
 var each       = require("lodash/collection/each");
-var defaults   = require("lodash/object/defaults");
-var isFunction = require("lodash/lang/isFunction");
+var t          = require("./types");
 
 function File(opts) {
   this.dynamicImportIds = {};
@@ -24,7 +25,7 @@ function File(opts) {
   this.data             = {};
 
   this.lastStatements   = [];
-  this.opts             = this.normaliseOptions(opts);
+  this.opts             = this.normalizeOptions(opts);
   this.ast              = {};
 
   this.buildTransformers();
@@ -50,7 +51,9 @@ File.helpers = [
   "typeof",
   "extends",
   "get",
-  "set"
+  "set",
+  "class-call-check",
+  "object-destructuring-empty"
 ];
 
 File.validOptions = [
@@ -85,7 +88,7 @@ File.validOptions = [
   "accept"
 ];
 
-File.prototype.normaliseOptions = function (opts) {
+File.prototype.normalizeOptions = function (opts) {
   opts = clone(opts);
 
   for (var key in opts) {
@@ -115,9 +118,11 @@ File.prototype.normaliseOptions = function (opts) {
     ast:                    true
   });
 
-  // normalise windows path separators to unix
+  // normalize windows path separators to unix
   opts.filename = opts.filename.replace(/\\/g, "/");
 
+  opts.basename = path.basename(opts.filename, path.extname(opts.filename));
+
   opts.blacklist = util.arrayify(opts.blacklist);
   opts.whitelist = util.arrayify(opts.whitelist);
   opts.optional  = util.arrayify(opts.optional);
@@ -177,6 +182,7 @@ File.prototype.buildTransformers = function () {
 
     if (pass.canRun(file)) {
       stack.push(pass);
+
       if (transformer.secondPass) {
         secondaryStack.push(pass);
       }
@@ -348,6 +354,8 @@ File.prototype.transform = function (ast) {
     modFormatter.init();
   }
 
+  this.checkNode(ast);
+
   var astRun = function (key) {
     each(self.transformerStack, function (pass) {
       pass.astRun(key);
@@ -363,6 +371,30 @@ File.prototype.transform = function (ast) {
   astRun("exit");
 };
 
+var checkTransformerVisitor = {
+  enter: function (node, parent, scope, context, state) {
+    state.check(node, scope);
+  }
+};
+
+File.prototype.checkNode = function (node, scope) {
+  var self = this;
+  scope = scope || this.scope;
+
+  var check = function (node, scope) {
+    each(self.transformerStack, function (pass) {
+      if (pass.shouldRun) return;
+      pass.checkNode(node, scope);
+    });
+  };
+
+  check(node, scope);
+
+  scope.traverse(node, checkTransformerVisitor, {
+    check: check
+  });
+};
+
 File.prototype.generate = function () {
   var opts = this.opts;
   var ast  = this.ast;
@@ -402,14 +434,14 @@ File.prototype.generateUid = function (name, scope) {
   do {
     uid = this._generateUid(name, i);
     i++;
-  } while (scope.has(uid));
+  } while (scope.hasReference(uid));
   return uid;
 };
 
 File.prototype.generateUidIdentifier = function (name, scope) {
   scope = scope || this.scope;
   var id = t.identifier(this.generateUid(name, scope));
-  scope.add(id);
+  scope.addDeclarationToFunctionScope("var", id);
   return id;
 };
 

lib/6to5/generation/buffer.js

@@ -19,7 +19,7 @@ Buffer.prototype.get = function () {
 };
 
 Buffer.prototype.getIndent = function () {
-  if (this.format.compact) {
+  if (this.format.compact || this.format.concise) {
     return "";
   } else {
     return util.repeat(this._indent, this.format.indent.style);
@@ -53,10 +53,12 @@ Buffer.prototype.rightBrace = function () {
 
 Buffer.prototype.keyword = function (name) {
   this.push(name);
-  this.push(" ");
+  this.space();
 };
 
 Buffer.prototype.space = function () {
+  if (this.format.compact) return;
+
   if (this.buf && !this.isLast([" ", "\n"])) {
     this.push(" ");
   }
@@ -70,7 +72,7 @@ Buffer.prototype.removeLast = function (cha) {
 };
 
 Buffer.prototype.newline = function (i, removeLast) {
-  if (this.format.compact) {
+  if (this.format.compact || this.format.concise) {
     this.space();
     return;
   }

lib/6to5/generation/generators/expressions.js

@@ -17,7 +17,7 @@ exports.UnaryExpression = function (node, print) {
   }
 
   this.push(node.operator);
-  if (hasSpace) this.space();
+  if (hasSpace) this.push(" ");
   print(node.argument);
 };
 
@@ -33,9 +33,13 @@ exports.UpdateExpression = function (node, print) {
 
 exports.ConditionalExpression = function (node, print) {
   print(node.test);
-  this.push(" ? ");
+  this.space();
+  this.push("?");
+  this.space();
   print(node.consequent);
-  this.push(" : ");
+  this.space();
+  this.push(":");
+  this.space();
   print(node.alternate);
 };
 
@@ -44,13 +48,13 @@ exports.NewExpression = function (node, print) {
   print(node.callee);
   if (node.arguments.length || this.format.parentheses) {
     this.push("(");
-    print.join(node.arguments, { separator: ", " });
+    print.list(node.arguments);
     this.push(")");
   }
 };
 
 exports.SequenceExpression = function (node, print) {
-  print.join(node.expressions, { separator: ", " });
+  print.list(node.expressions);
 };
 
 exports.ThisExpression = function () {
@@ -72,9 +76,7 @@ exports.CallExpression = function (node, print) {
     separator += " ";
   }
 
-  print.join(node.arguments, {
-    separator: separator
-  });
+  print.list(node.arguments, { separator: separator });
 
   if (node._prettyCall) {
     this.newline();
@@ -115,10 +117,11 @@ exports.BinaryExpression =
 exports.LogicalExpression =
 exports.AssignmentPattern =
 exports.AssignmentExpression = function (node, print) {
+  // todo: add cases where the spaces can be dropped when in compact mode
   print(node.left);
-  this.space();
+  this.push(" ");
   this.push(node.operator);
-  this.space();
+  this.push(" ");
   print(node.right);
 };
 

lib/6to5/generation/generators/jsx.js

@@ -75,6 +75,4 @@ exports.JSXClosingElement = function (node, print) {
   this.push(">");
 };
 
-exports.JSXEmptyExpression = function () {
-
-};
+exports.JSXEmptyExpression = function () {};

lib/6to5/generation/generators/methods.js

@@ -4,11 +4,7 @@ var t = require("../../types");
 
 exports._params = function (node, print) {
   this.push("(");
-
-  print.join(node.params, {
-    separator: ", "
-  });
-
+  print.list(node.params);
   this.push(")");
 };
 
@@ -45,11 +41,14 @@ exports.FunctionExpression = function (node, print) {
   if (node.async) this.push("async ");
   this.push("function");
   if (node.generator) this.push("*");
-  this.push(" ");
+
   if (node.id) {
-    this.space();
+    this.push(" ");
     print(node.id);
+  } else {
+    this.space();
   }
+
   this._params(node, print);
   this.space();
   print(node.body);

lib/6to5/generation/generators/statements.js

@@ -23,6 +23,11 @@ exports.IfStatement = function (node, print) {
   if (node.alternate) {
     if (this.isLast("}")) this.push(" ");
     this.keyword("else");
+
+    if (this.format.format && !t.isBlockStatement(node.alternate)) {
+      this.push(" ");
+    }
+
     print.indentOnComments(node.alternate);
   }
 };
@@ -190,7 +195,7 @@ exports.VariableDeclaration = function (node, print, parent) {
     sep += " ";
   }
 
-  print.join(node.declarations, { separator: sep });
+  print.list(node.declarations, { separator: sep });
 
   if (!t.isFor(parent)) {
     this.semicolon();

lib/6to5/generation/generators/types.js

@@ -27,7 +27,7 @@ exports.ObjectPattern = function (node, print) {
     this.push("{");
     this.space();
 
-    print.join(props, { separator: ", ", indent: true });
+    print.list(props, { indent: true });
 
     this.space();
     this.push("}");
@@ -49,7 +49,8 @@ exports.Property = function (node, print) {
       if (node.shorthand) return;
     }
 
-    this.push(": ");
+    this.push(":");
+    this.space();
     print(node.value);
   }
 };
@@ -71,7 +72,7 @@ exports.ArrayPattern = function (node, print) {
       // both (all) of the holes.
       self.push(",");
     } else {
-      if (i > 0) self.push(" ");
+      if (i > 0 && !self.format.compact) self.push(" ");
       print(elem);
       if (i < len - 1) self.push(",");
     }
@@ -93,8 +94,10 @@ exports.Literal = function (node) {
     });
 
     this.push(val);
-  } else if (type === "boolean" || type === "number") {
-    this.push(JSON.stringify(val));
+  } else if (type === "number") {
+    this.push(val + "");
+  } else if (type === "boolean") {
+    this.push(val ? "true" : "false");
   } else if (node.regex) {
     this.push("/" + node.regex.pattern + "/" + node.regex.flags);
   } else if (val === null) {

lib/6to5/generation/index.js

@@ -24,7 +24,7 @@ function CodeGenerator(ast, opts, code) {
 
   this.comments = ast.comments || [];
   this.tokens   = ast.tokens || [];
-  this.format   = CodeGenerator.normaliseOptions(code, opts);
+  this.format   = CodeGenerator.normalizeOptions(code, opts);
   this.ast      = ast;
 
   this.whitespace = new Whitespace(this.tokens, this.comments);
@@ -39,7 +39,7 @@ each(Buffer.prototype, function (fn, key) {
   };
 });
 
-CodeGenerator.normaliseOptions = function (code, opts) {
+CodeGenerator.normalizeOptions = function (code, opts) {
   var style = "  ";
   if (code) {
     var indent = detectIndent(code).indent;
@@ -50,6 +50,7 @@ CodeGenerator.normaliseOptions = function (code, opts) {
     parentheses: true,
     comments: opts.comments == null || opts.comments,
     compact: false,
+    concise: false,
     indent: {
       adjustMultilineComment: true,
       style: style,
@@ -111,6 +112,16 @@ CodeGenerator.prototype.buildPrint = function (parent) {
     return self.printJoin(print, nodes, opts);
   };
 
+  print.list = function (items, opts) {
+    opts = opts || {};
+
+    var sep = opts.separator || ", ";
+    if (self.format.compact) sep = ",";
+    opts.separator = sep;
+
+    print.join(items, opts);
+  };
+
   print.block = function (node) {
     return self.printBlock(print, node);
   };
@@ -129,9 +140,9 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
     node._compact = true;
   }
 
-  var oldCompact = this.format.compact;
+  var oldConcise = this.format.concise;
   if (node._compact) {
-    this.format.compact = true;
+    this.format.concise = true;
   }
 
   var self = this;
@@ -179,7 +190,7 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
     newline(true);
 
     if (opts.before) opts.before();
-    this.map.mark(node);
+    this.map.mark(node, "start");
 
     this[node.type](node, this.buildPrint(node), parent);
 
@@ -189,6 +200,7 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
     }
     if (needsParens) this.push(")");
 
+    this.map.mark(node, "end");
     if (opts.after) opts.after();
 
     newline(false);
@@ -198,7 +210,7 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
     throw new ReferenceError("unknown node of type " + JSON.stringify(node.type) + " with constructor " + JSON.stringify(node && node.constructor.name));
   }
 
-  this.format.compact = oldCompact;
+  this.format.concise = oldConcise;
 };
 
 CodeGenerator.prototype.printJoin = function (print, nodes, opts) {

lib/6to5/generation/source-map.js

@@ -30,7 +30,7 @@ SourceMap.prototype.get = function () {
   }
 };
 
-SourceMap.prototype.mark = function (node) {
+SourceMap.prototype.mark = function (node, type) {
   var loc = node.loc;
   if (!loc) return; // no location info
 
@@ -46,7 +46,7 @@ SourceMap.prototype.mark = function (node) {
     column: position.column
   };
 
-  var original = loc.start;
+  var original = loc[type];
 
   map.addMapping({
     source: this.opts.sourceFileName,

lib/6to5/register-cache.js

@@ -12,14 +12,6 @@ exports.save = function () {
 };
 
 exports.load = function () {
-  if (!fs.existsSync(FILENAME)) return;
-
-  try {
-    data = JSON.parse(fs.readFileSync(FILENAME));
-  } catch (err) {
-    return;
-  }
-
   process.on("exit", exports.save);
 
   var sigint = function () {
@@ -29,6 +21,14 @@ exports.load = function () {
   };
 
   process.on("SIGINT", sigint);
+
+  if (!fs.existsSync(FILENAME)) return;
+
+  try {
+    data = JSON.parse(fs.readFileSync(FILENAME));
+  } catch (err) {
+    return;
+  }
 };
 
 exports.get = function () {

lib/6to5/register.js

@@ -72,16 +72,27 @@ var shouldIgnore = function (filename) {
   return (ignoreRegex && ignoreRegex.test(filename)) || (onlyRegex && !onlyRegex.test(filename));
 };
 
-var istanbulLoader = function (m, filename, old) {
+var istanbulMonkey = {};
+
+if (process.env.running_under_istanbul) { // jshint ignore:line
   // we need to monkey patch fs.readFileSync so we can hook into
   // what istanbul gets, it's extremely dirty but it's the only way
   var _readFileSync = fs.readFileSync;
 
-  fs.readFileSync = function () {
-    fs.readFileSync = _readFileSync;
-    return compile(filename);
+  fs.readFileSync = function (filename) {
+    if (istanbulMonkey[filename]) {
+      delete istanbulMonkey[filename];
+      var code = compile(filename);
+      istanbulMonkey[filename] = true;
+      return code;
+    } else {
+      return _readFileSync.apply(this, arguments);
+    }
   };
+}
 
+var istanbulLoader = function (m, filename, old) {
+  istanbulMonkey[filename] = true;
   old(m, filename);
 };
 
@@ -120,7 +131,7 @@ var hookExtensions = function (_exts) {
 hookExtensions(util.canCompile.EXTENSIONS);
 
 module.exports = function (opts) {
-  // normalise options
+  // normalize options
   opts = opts || {};
 
   if (opts.only != null) onlyRegex = util.regexify(opts.only);

lib/6to5/transformation/helpers/define-map.js

@@ -0,0 +1,73 @@
+var cloneDeep = require("lodash/lang/cloneDeep");
+var traverse  = require("../../traverse");
+var clone      = require("lodash/lang/clone");
+var each      = require("lodash/collection/each");
+var has       = require("lodash/object/has");
+var t         = require("../../types");
+
+exports.push = function (mutatorMap, key, kind, computed, value) {
+  var alias;
+
+  if (t.isIdentifier(key)) {
+    alias = key.name;
+    if (computed) alias = "computed:" + alias;
+  } else if (t.isLiteral(key)) {
+    alias = String(key.value);
+  } else {
+    alias = JSON.stringify(traverse.removeProperties(cloneDeep(key)));
+  }
+
+  var map;
+  if (has(mutatorMap, alias)) {
+    map = mutatorMap[alias];
+  } else {
+    map = {};
+  }
+  mutatorMap[alias] = map;
+
+  map._key = key;
+  if (computed) {
+    map._computed = true;
+  }
+
+  map[kind] = value;
+};
+
+exports.build = function (mutatorMap) {
+  var objExpr = t.objectExpression([]);
+
+  each(mutatorMap, function (map) {
+    var mapNode = t.objectExpression([]);
+
+    var propNode = t.property("init", map._key, mapNode, map._computed);
+
+    if (!map.get && !map.set) {
+      map.writable = t.literal(true);
+    }
+
+    if (map.enumerable === false) {
+      delete map.enumerable;
+    } else {
+      map.enumerable = t.literal(true);
+    }
+
+    map.configurable = t.literal(true);
+
+    each(map, function (node, key) {
+      if (key[0] === "_") return;
+
+      node = clone(node);
+      var inheritNode = node;
+      if (t.isMethodDefinition(node)) node = node.value;
+
+      var prop = t.property("init", t.identifier(key), node);
+      t.inheritsComments(prop, inheritNode);
+      t.removeComments(inheritNode);
+      mapNode.properties.push(prop);
+    });
+
+    objExpr.properties.push(propNode);
+  });
+
+  return objExpr;
+};

lib/6to5/transformation/helpers/explode-assignable-expression.js

@@ -5,7 +5,7 @@ var t = require("../../types");
 var getObjRef = function (node, nodes, file, scope) {
   var ref;
   if (t.isIdentifier(node)) {
-    if (scope.has(node.name, true)) {
+    if (scope.hasBinding(node.name)) {
       // this variable is declared in scope so we can be 100% sure
       // that evaluating it multiple times wont trigger a getter
       // or something else
@@ -18,7 +18,7 @@ var getObjRef = function (node, nodes, file, scope) {
   } else if (t.isMemberExpression(node)) {
     ref = node.object;
 
-    if (t.isIdentifier(ref) && scope.has(ref.name)) {
+    if (t.isIdentifier(ref) && scope.hasReference(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

lib/6to5/transformation/helpers/name-method.js

@@ -1,8 +1,7 @@
 "use strict";
 
-var traverse = require("../../traverse");
-var util     = require("../../util");
-var t        = require("../../types");
+var util = require("../../util");
+var t    = require("../../types");
 
 var visitor = {
   enter: function (node, parent, scope, context, state) {
@@ -14,7 +13,7 @@ var visitor = {
 
     // check that we don't have a local variable declared as that removes the need
     // for the wrapper
-    var localDeclar = scope.get(state.id, true);
+    var localDeclar = scope.getBinding(state.id);
     if (localDeclar !== state.outerDeclar) return;
 
     state.selfReference = true;
@@ -32,10 +31,10 @@ exports.property = function (node, file, scope) {
   var state = {
     id: id,
     selfReference: false,
-    outerDeclar: scope.get(id, true),
+    outerDeclar: scope.getBinding(id),
   };
 
-  traverse(node, visitor, scope, state);
+  scope.traverse(node, visitor, state);
 
   if (state.selfReference) {
     // todo: support generators

lib/6to5/transformation/helpers/remap-async-to-generator.js

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../traverse");
-var t        = require("../../types");
+var t = require("../../types");
 
 var visitor = {
   enter: function (node, parent, scope, context) {
@@ -23,7 +22,7 @@ module.exports = function (node, callId, scope) {
   node.async = false;
   node.generator = true;
 
-  traverse(node, visitor, scope);
+  scope.traverse(node, visitor);
 
   var call = t.callExpression(callId, [node]);
   var id = node.id;

lib/6to5/transformation/helpers/replace-supers.js

@@ -2,8 +2,7 @@
 
 module.exports = ReplaceSupers;
 
-var traverse = require("../../traverse");
-var t        = require("../../types");
+var t = require("../../types");
 
 /**
  * Description
@@ -38,12 +37,7 @@ ReplaceSupers.prototype.setSuperProperty = function (property, value, isStatic,
   return t.callExpression(
     this.file.addHelper("set"),
     [
-      t.callExpression(
-        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
-        [
-          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
-        ]
-      ),
+      isStatic ? this.superName : t.memberExpression(this.superName, t.identifier("prototype")),
       isComputed ? property : t.literal(property.name),
       value,
       thisExpression
@@ -65,22 +59,81 @@ ReplaceSupers.prototype.setSuperProperty = function (property, value, isStatic,
  * @returns {Node}
  */
 
-ReplaceSupers.prototype.superProperty = function (property, isStatic, isComputed, thisExpression) {
+ReplaceSupers.prototype.getSuperProperty = function (property, isStatic, isComputed, thisExpression) {
   return t.callExpression(
     this.file.addHelper("get"),
     [
-      t.callExpression(
-        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
-        [
-          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
-        ]
-      ),
+      isStatic ? this.superName : t.memberExpression(this.superName, t.identifier("prototype")),
       isComputed ? property : t.literal(property.name),
       thisExpression
     ]
   );
 };
 
+/**
+ * Description
+ */
+
+ReplaceSupers.prototype.replace = function () {
+  this.traverseLevel(this.methodNode.value, true);
+};
+
+var visitor = {
+  enter: function (node, parent, scope, context, state) {
+    var topLevel = state.topLevel;
+    var self = state.self;
+
+    if (t.isFunction(node) && !t.isArrowFunctionExpression(node)) {
+      // we need to call traverseLevel again so we're context aware
+      self.traverseLevel(node, false);
+      return context.skip();
+    }
+
+    if (t.isProperty(node, { method: true }) || t.isMethodDefinition(node)) {
+      // break on object methods
+      return context.skip();
+    }
+
+    var getThisReference = topLevel ?
+      // top level so `this` is the instance
+      t.thisExpression :
+      // not in the top level so we need to create a reference
+      self.getThisReference.bind(self);
+
+    var callback = self.specHandle;
+    if (self.isLoose) callback = self.looseHandle;
+    return callback.call(self, getThisReference, node, parent);
+  }
+};
+
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Boolean} topLevel
+ */
+
+ReplaceSupers.prototype.traverseLevel = function (node, topLevel) {
+  var state = { self: this, topLevel: topLevel };
+  this.scope.traverse(node, visitor, state);
+};
+
+/**
+ * Description
+ */
+
+ReplaceSupers.prototype.getThisReference = function () {
+  if (this.topLevelThisReference) {
+    return this.topLevelThisReference;
+  } else {
+    var ref = this.topLevelThisReference = this.file.generateUidIdentifier("this");
+    this.methodNode.value.body.body.unshift(t.variableDeclaration("var", [
+      t.variableDeclarator(this.topLevelThisReference, t.thisExpression())
+    ]));
+    return ref;
+  }
+};
+
 /**
  * Description
  *
@@ -90,7 +143,7 @@ ReplaceSupers.prototype.superProperty = function (property, isStatic, isComputed
  * @returns {Object}
  */
 
-ReplaceSupers.prototype.looseSuperProperty = function (methodNode, id, parent) {
+ReplaceSupers.prototype.getLooseSuperProperty = function (methodNode, id, parent) {
   var methodName = methodNode.key;
   var superName  = this.superName || t.identifier("Function");
 
@@ -122,70 +175,6 @@ ReplaceSupers.prototype.looseSuperProperty = function (methodNode, id, parent) {
   }
 };
 
-/**
- * Description
- */
-
-ReplaceSupers.prototype.replace = function () {
-  this.traverseLevel(this.methodNode.value, true);
-};
-
-var visitor = {
-  enter: function (node, parent, scope, context, state) {
-    var topLevel = state.topLevel;
-    var self = state.self;
-
-    if (t.isFunction(node) && !t.isArrowFunctionExpression(node)) {
-      // we need to call traverseLevel again so we're context aware
-      self.traverseLevel(node, false);
-      return context.skip();
-    }
-
-    if (t.isProperty(node, { method: true }) || t.isMethodDefinition(node)) {
-      // break on object methods
-      return context.skip();
-    }
-
-    var getThisReference = topLevel ?
-      // top level so `this` is the instance
-      t.thisExpression :
-      // not in the top level so we need to create a reference
-      self.getThisReference;
-
-    var callback = self.specHandle;
-    if (self.isLoose) callback = self.looseHandle;
-    return callback.call(self, getThisReference, node, parent);
-  }
-};
-
-/**
- * Description
- *
- * @param {Object} node
- * @param {Boolean} topLevel
- */
-
-ReplaceSupers.prototype.traverseLevel = function (node, topLevel) {
-  var state = { self: this, topLevel: topLevel };
-  traverse(node, visitor, this.scope, state);
-};
-
-/**
- * Description
- */
-
-ReplaceSupers.prototype.getThisReference = function () {
-  if (this.topLevelThisReference) {
-    return this.topLevelThisReference;
-  } else {
-    var ref = this.topLevelThisReference = this.file.generateUidIdentifier("this");
-    this.methodNode.value.body.body.unshift(t.variableDeclaration("var", [
-      t.variableDeclarator(this.topLevelThisReference, t.thisExpression())
-    ]));
-    return ref;
-  }
-};
-
 /**
  * Description
  *
@@ -196,7 +185,7 @@ ReplaceSupers.prototype.getThisReference = function () {
 
 ReplaceSupers.prototype.looseHandle = function (getThisReference, node, parent) {
   if (t.isIdentifier(node, { name: "super" })) {
-    return this.looseSuperProperty(this.methodNode, node, parent);
+    return this.getLooseSuperProperty(this.methodNode, node, parent);
   } else if (t.isCallExpression(node)) {
     var callee = node.callee;
     if (!t.isMemberExpression(callee)) return;
@@ -269,7 +258,7 @@ ReplaceSupers.prototype.specHandle = function (getThisReference, node, parent) {
   if (!property) return;
 
   thisReference = getThisReference();
-  var superProperty = this.superProperty(property, methodNode.static, computed, thisReference);
+  var superProperty = this.getSuperProperty(property, methodNode.static, computed, thisReference);
   if (args) {
     if (args.length === 1 && t.isSpreadElement(args[0])) {
       // super(...arguments);

lib/6to5/transformation/index.js

@@ -14,7 +14,7 @@ function transform(code, opts) {
 }
 
 transform.fromAst = function (ast, code, opts) {
-  ast = util.normaliseAst(ast);
+  ast = util.normalizeAst(ast);
 
   var file = new File(opts);
   file.addCode(code);

lib/6to5/transformation/modules/_default.js

@@ -2,7 +2,6 @@
 
 module.exports = DefaultFormatter;
 
-var traverse = require("../../traverse");
 var object   = require("../../helpers/object");
 var util     = require("../../util");
 var t        = require("../../types");
@@ -45,7 +44,7 @@ var exportsVisitor = {
       formatter.hasLocalImports = true;
 
       if (declar && t.isStatement(declar)) {
-        extend(formatter.localExports, t.getDeclarations(declar));
+        extend(formatter.localExports, t.getBindingIdentifiers(declar));
       }
 
       if (!node.default) {
@@ -60,21 +59,21 @@ var exportsVisitor = {
 };
 
 DefaultFormatter.prototype.getLocalExports = function () {
-  traverse(this.file.ast, exportsVisitor, this.file.scope, this);
+  this.file.scope.traverse(this.file.ast, exportsVisitor, this);
 };
 
 var importsVisitor = {
   enter: function (node, parent, scope, context, formatter) {
     if (t.isImportDeclaration(node)) {
       formatter.hasLocalImports = true;
-      extend(formatter.localImports, t.getDeclarations(node));
+      extend(formatter.localImports, t.getBindingIdentifiers(node));
       formatter.bumpImportOccurences(node);
     }
   }
 };
 
 DefaultFormatter.prototype.getLocalImports = function () {
-  traverse(this.file.ast, importsVisitor, this.file.scope, this);
+  this.file.scope.traverse(this.file.ast, importsVisitor, this);
 };
 
 var remapVisitor = {
@@ -116,7 +115,7 @@ var remapVisitor = {
 
 DefaultFormatter.prototype.remapAssignments = function () {
   if (this.hasLocalImports) {
-    traverse(this.file.ast, remapVisitor, this.file.scope, this);
+    this.file.scope.traverse(this.file.ast, remapVisitor, this);
   }
 };
 
@@ -147,7 +146,7 @@ DefaultFormatter.prototype.remapExportAssignment = function (node) {
 DefaultFormatter.prototype.isLocalReference = function (node, scope) {
   var localExports = this.localExports;
   var name = node.name;
-  return t.isIdentifier(node) && localExports[name] && localExports[name] === scope.get(name, true);
+  return t.isIdentifier(node) && localExports[name] && localExports[name] === scope.getBinding(name);
 };
 
 DefaultFormatter.prototype.getModuleName = function () {
@@ -171,12 +170,12 @@ DefaultFormatter.prototype.getModuleName = function () {
 
   if (!opts.keepModuleIdExtensions) {
     // remove extension
-    filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+    filenameRelative = filenameRelative.replace(/\.(\w*?)$/, "");
   }
 
   moduleName += filenameRelative;
 
-  // normalise path separators
+  // normalize path separators
   moduleName = moduleName.replace(/\\/g, "/");
 
   return moduleName;
@@ -212,6 +211,12 @@ DefaultFormatter.prototype.getExternalReference = function (node, nodes) {
   }
 };
 
+DefaultFormatter.prototype.checkExportIdentifier = function (node) {
+  if (t.isIdentifier(node, { name: "__esModule" })) {
+    throw this.file.errorWithNode(node, "Illegal export __esModule - this is used internally for CommonJS interop");
+  }
+};
+
 DefaultFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
   var inherits = false;
   if (node.specifiers.length === 1) inherits = node;
@@ -224,7 +229,7 @@ DefaultFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
       nodes.push(this.buildExportsWildcard(ref, node));
     } else {
       if (t.isSpecifierDefault(specifier) && !this.noInteropRequire) {
-        // importing a default so we need to normalise it
+        // importing a default so we need to normalize it
         ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
       } else {
         ref = t.memberExpression(ref, t.getSpecifierId(specifier));
@@ -251,6 +256,7 @@ DefaultFormatter.prototype.buildExportsWildcard = function (objectIdentifier) {
 };
 
 DefaultFormatter.prototype.buildExportsAssignment = function (id, init) {
+  this.checkExportIdentifier(id);
   return util.template("exports-assign", {
     VALUE: init,
     KEY:   id

lib/6to5/transformation/modules/system.js

@@ -5,7 +5,6 @@ module.exports = SystemFormatter;
 var DefaultFormatter = require("./_default");
 var AMDFormatter     = require("./amd");
 var useStrict        = require("../helpers/use-strict");
-var traverse         = require("../../traverse");
 var util             = require("../../util");
 var t                = require("../../types");
 var last             = require("lodash/array/last");
@@ -97,7 +96,7 @@ SystemFormatter.prototype.buildRunnerSetters = function (block, hoistDeclarators
       hoistDeclarators: hoistDeclarators
     };
 
-    traverse(block, runnerSettersVisitor, scope, state);
+    scope.traverse(block, runnerSettersVisitor, state);
 
     return t.functionExpression(null, [uid], t.blockStatement(state.nodes));
   }));
@@ -182,7 +181,7 @@ SystemFormatter.prototype.transform = function (ast) {
   var returnStatement = handlerBody.pop();
 
   // hoist up all variable declarations
-  traverse(block, hoistVariablesVisitor, this.file.scope, hoistDeclarators);
+  this.file.scope.traverse(block, hoistVariablesVisitor, hoistDeclarators);
 
   if (hoistDeclarators.length) {
     var hoistDeclar = t.variableDeclaration("var", hoistDeclarators);
@@ -191,7 +190,7 @@ SystemFormatter.prototype.transform = function (ast) {
   }
 
   // hoist up function declarations for circular references
-  traverse(block, hoistFunctionsVisitor, this.file.scope, handlerBody);
+  this.file.scope.traverse(block, hoistFunctionsVisitor, handlerBody);
 
   handlerBody.push(returnStatement);
 

lib/6to5/transformation/templates/class-call-check.js

@@ -0,0 +1,5 @@
+(function (instance, Constructor) {
+  if (!(instance instanceof Constructor)) {
+    throw new TypeError("Cannot call a class as a function");
+  }
+});

lib/6to5/transformation/templates/class-super-constructor-call.js

@@ -1,3 +1,3 @@
-if (Object.getPrototypeOf(CLASS_NAME) !== null) {
-  Object.getPrototypeOf(CLASS_NAME).apply(this, arguments);
+if (SUPER_NAME != null) {
+  SUPER_NAME.apply(this, arguments);
 }

lib/6to5/transformation/templates/object-destructuring-empty.js

@@ -0,0 +1,3 @@
+(function (obj) {
+  if (obj == null) throw new TypeError("Cannot destructure undefined");
+});

lib/6to5/transformation/transformer-pass.js

@@ -1,6 +1,5 @@
 module.exports = TransformerPass;
 
-var traverse = require("../traverse");
 var util     = require("../util");
 var contains = require("lodash/collection/contains");
 
@@ -11,11 +10,14 @@ var contains = require("lodash/collection/contains");
 
 function TransformerPass(file, transformer) {
   this.transformer = transformer;
+  this.shouldRun   = !transformer.check;
   this.handlers    = transformer.handlers;
   this.file        = file;
 }
 
 TransformerPass.prototype.astRun = function (key) {
+  if (!this.shouldRun) return;
+
   var handlers = this.handlers;
   var file = this.file;
 
@@ -29,23 +31,39 @@ TransformerPass.prototype.canRun = function () {
 
   var opts = this.file.opts;
   var key  = transformer.key;
+
+  // internal
   if (key[0] === "_") return true;
 
+  // blacklist
   var blacklist = opts.blacklist;
   if (blacklist.length && contains(blacklist, key)) return false;
 
+  // whitelist
   var whitelist = opts.whitelist;
   if (whitelist.length && !contains(whitelist, key)) return false;
 
+  // optional
   if (transformer.optional && !contains(opts.optional, key)) return false;
 
+  // experimental
   if (transformer.experimental && !opts.experimental) return false;
 
+  // playground
   if (transformer.playground && !opts.playground) return false;
 
   return true;
 };
 
+TransformerPass.prototype.checkNode = function (node) {
+  var check = this.transformer.check;
+  if (check) {
+    return this.shouldRun = check(node);
+  } else {
+    return true;
+  }
+};
+
 var transformVisitor = {
   enter: function (node, parent, scope, context, state) {
     var fns = state.handlers[node.type];
@@ -61,6 +79,8 @@ var transformVisitor = {
 };
 
 TransformerPass.prototype.transform = function () {
+  if (!this.shouldRun) return;
+
   var file = this.file;
 
   util.debug(file.opts.filename + ": Running transformer " + this.transformer.key);
@@ -68,7 +88,7 @@ TransformerPass.prototype.transform = function () {
   this.astRun("before");
 
   var state = { file: file, handlers: this.handlers, pass: this };
-  traverse(file.ast, transformVisitor, file.scope, state);
+  file.scope.traverse(file.ast, transformVisitor, state);
 
   this.astRun("after");
 };

lib/6to5/transformation/transformer.js

@@ -16,16 +16,19 @@ var each            = require("lodash/collection/each");
 
 function Transformer(key, transformer, opts) {
   this.manipulateOptions = transformer.manipulateOptions;
-  this.experimental      = !!transformer.experimental;
-  this.playground        = !!transformer.playground;
-  this.secondPass        = !!transformer.secondPass;
-  this.optional          = !!transformer.optional;
-  this.handlers          = this.normalise(transformer);
-  this.opts              = opts || {};
-  this.key               = key;
+  this.check             = transformer.check;
+
+  this.experimental = !!transformer.experimental;
+  this.playground   = !!transformer.playground;
+  this.secondPass   = !!transformer.secondPass;
+  this.optional     = !!transformer.optional;
+
+  this.handlers = this.normalize(transformer);
+  this.opts     = opts || {};
+  this.key      = key;
 }
 
-Transformer.prototype.normalise = function (transformer) {
+Transformer.prototype.normalize = function (transformer) {
   var self = this;
 
   if (isFunction(transformer)) {

lib/6to5/transformation/transformers/deprecated.json

@@ -12,7 +12,8 @@
   "generatorComprehension": "es7.comprehensions",
   "arrowFunctions": "es6.arrowFunctions",
   "classes": "es6.classes",
-  "objectSpread": "es7.objectSpread",
+  "objectSpread": "es7.objectRestSpread",
+  "es7.objectSpread": "es7.objectRestSpread",
   "exponentiationOperator": "es7.exponentiationOperator",
   "spread": "es6.spread",
   "templateLiterals": "es6.templateLiterals",

lib/6to5/transformation/transformers/es5/properties.mutators.js

@@ -1,7 +1,11 @@
 "use strict";
 
-var util = require("../../../util");
-var t    = require("../../../types");
+var defineMap = require("../../helpers/define-map");
+var t         = require("../../../types");
+
+exports.check = function (node) {
+  return t.isProperty(node) && (node.kind === "get" || node.kind === "set");
+};
 
 exports.ObjectExpression = function (node) {
   var mutatorMap = {};
@@ -10,7 +14,7 @@ exports.ObjectExpression = function (node) {
   node.properties = node.properties.filter(function (prop) {
     if (prop.kind === "get" || prop.kind === "set") {
       hasAny = true;
-      util.pushMutatorMap(mutatorMap, prop.key, prop.kind, prop.computed, prop.value);
+      defineMap.push(mutatorMap, prop.key, prop.kind, prop.computed, prop.value);
       return false;
     } else {
       return true;
@@ -21,6 +25,6 @@ exports.ObjectExpression = function (node) {
 
   return t.callExpression(
     t.memberExpression(t.identifier("Object"), t.identifier("defineProperties")),
-    [node, util.buildDefineProperties(mutatorMap)]
+    [node, defineMap.build(mutatorMap)]
   );
 };

lib/6to5/transformation/transformers/es6/arrow-functions.js

@@ -2,6 +2,8 @@
 
 var t = require("../../../types");
 
+exports.check = t.isArrowFunctionExpression;
+
 exports.ArrowFunctionExpression = function (node) {
   t.ensureBlock(node);
 

lib/6to5/transformation/transformers/es6/block-scoping-tdz.js

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
 
 var visitor = {
   enter: function (node, parent, scope, context, state) {
@@ -11,7 +10,7 @@ var visitor = {
     if (!declared) return;
 
     // declared node is different in this scope
-    if (scope.get(node.name, true) !== declared) return;
+    if (scope.getBinding(node.name) !== declared) return;
 
     var declaredLoc  = declared.loc;
     var referenceLoc = node.loc;
@@ -46,5 +45,5 @@ exports.BlockStatement = function (node, parent, scope, context, file) {
     file:    file
   };
 
-  traverse(node, visitor, scope, state);
+  scope.traverse(node, visitor, state);
 };

lib/6to5/transformation/transformers/es6/block-scoping.js

@@ -7,6 +7,10 @@ var t        = require("../../../types");
 var values   = require("lodash/object/values");
 var extend   = require("lodash/object/extend");
 
+exports.check = function (node) {
+  return t.isVariableDeclaration(node) && (node.kind === "let" || node.kind === "const");
+};
+
 var isLet = function (node, parent) {
   if (!t.isVariableDeclaration(node)) return false;
   if (node._let) return true;
@@ -29,7 +33,7 @@ var isVar = function (node, parent) {
   return t.isVariableDeclaration(node, { kind: "var" }) && !isLet(node, parent);
 };
 
-var standardiseLets = function (declars) {
+var standardizeLets = function (declars) {
   for (var i = 0; i < declars.length; i++) {
     delete declars[i]._let;
   }
@@ -45,15 +49,15 @@ exports.Loop = function (node, parent, scope, context, file) {
     t.ensureBlock(node);
     node.body._letDeclarators = [init];
   }
-  var letScoping = new LetScoping(node, node.body, parent, scope, file);
-  letScoping.run();
+  var blockScoping = new BlockScoping(node, node.body, parent, scope, file);
+  blockScoping.run();
 };
 
 exports.Program =
 exports.BlockStatement = function (block, parent, scope, context, file) {
   if (!t.isLoop(parent)) {
-    var letScoping = new LetScoping(false, block, parent, scope, file);
-    letScoping.run();
+    var blockScoping = new BlockScoping(false, block, parent, scope, file);
+    blockScoping.run();
   }
 };
 
@@ -67,7 +71,7 @@ exports.BlockStatement = function (block, parent, scope, context, file) {
  * @param {File} file
  */
 
-function LetScoping(loopParent, block, parent, scope, file) {
+function BlockScoping(loopParent, block, parent, scope, file) {
   this.loopParent = loopParent;
   this.parent     = parent;
   this.scope      = scope;
@@ -84,7 +88,7 @@ function LetScoping(loopParent, block, parent, scope, file) {
  * Start the ball rolling.
  */
 
-LetScoping.prototype.run = function () {
+BlockScoping.prototype.run = function () {
   var block = this.block;
   if (block._letDone) return;
   block._letDone = true;
@@ -110,11 +114,11 @@ function replace(node, parent, scope, context, remaps) {
   var remap = remaps[node.name];
   if (!remap) return;
 
-  var own = scope.get(node.name, true);
-  if (own === remap.node) {
+  var ownBinding = scope.getBinding(node.name);
+  if (ownBinding === remap.binding) {
     node.name = remap.uid;
   } else {
-    // scope already has it's own declaration that doesn't
+    // scope already has it's own binding that doesn't
     // match the one we have a stored replacement for
     if (context) context.skip();
   }
@@ -126,14 +130,14 @@ var replaceVisitor = {
 
 function traverseReplace(node, parent, scope, remaps) {
   replace(node, parent, scope, null, remaps);
-  traverse(node, replaceVisitor, scope, remaps);
+  scope.traverse(node, replaceVisitor, remaps);
 }
 
 /**
  * Description
  */
 
-LetScoping.prototype.remap = function () {
+BlockScoping.prototype.remap = function () {
   var hasRemaps = false;
   var letRefs   = this.letReferences;
   var scope     = this.scope;
@@ -149,13 +153,13 @@ LetScoping.prototype.remap = function () {
     // this is the defining identifier of a declaration
     var ref = letRefs[key];
 
-    if (scope.parentHas(key)) {
+    if (scope.parentHasReference(key)) {
       var uid = scope.generateUidIdentifier(ref.name).name;
       ref.name = uid;
 
       hasRemaps = true;
       remaps[key] = remaps[uid] = {
-        node: ref,
+        binding: ref,
         uid: uid
       };
     }
@@ -172,14 +176,14 @@ LetScoping.prototype.remap = function () {
     traverseReplace(loopParent.update, loopParent, scope, remaps);
   }
 
-  traverse(this.block, replaceVisitor, scope, remaps);
+  scope.traverse(this.block, replaceVisitor, remaps);
 };
 
 /**
  * Description
  */
 
-LetScoping.prototype.needsClosure = function () {
+BlockScoping.prototype.needsClosure = function () {
   var block = this.block;
 
   // if we're inside of a for loop then we search to see if there are any
@@ -227,7 +231,7 @@ var letReferenceFunctionVisitor = {
 
     // this scope has a variable with the same name so it couldn't belong
     // to our let scope
-    if (scope.hasOwn(node.name, true)) return;
+    if (scope.hasOwnBinding(node.name)) return;
 
     // not a part of our scope
     if (!state.letReferences[node.name]) return;
@@ -239,7 +243,7 @@ var letReferenceFunctionVisitor = {
 var letReferenceBlockVisitor = {
   enter: function (node, parent, scope, context, state) {
     if (t.isFunction(node)) {
-      traverse(node, letReferenceFunctionVisitor, scope, state);
+      scope.traverse(node, letReferenceFunctionVisitor, state);
       return context.skip();
     }
   }
@@ -249,7 +253,7 @@ var letReferenceBlockVisitor = {
  * Description
  */
 
-LetScoping.prototype.getLetReferences = function () {
+BlockScoping.prototype.getLetReferences = function () {
   var block = this.block;
 
   var declarators = block._letDeclarators || [];
@@ -258,7 +262,7 @@ LetScoping.prototype.getLetReferences = function () {
   //
   for (var i = 0; i < declarators.length; i++) {
     declar = declarators[i];
-    extend(this.outsideLetReferences, t.getDeclarations(declar));
+    extend(this.outsideLetReferences, t.getBindingIdentifiers(declar));
   }
 
   //
@@ -274,7 +278,7 @@ LetScoping.prototype.getLetReferences = function () {
   //
   for (i = 0; i < declarators.length; i++) {
     declar = declarators[i];
-    var keys = t.getDeclarations(declar);
+    var keys = t.getBindingIdentifiers(declar);
     extend(this.letReferences, keys);
     this.hasLetReferences = true;
   }
@@ -283,7 +287,7 @@ LetScoping.prototype.getLetReferences = function () {
   if (!this.hasLetReferences) return;
 
   // set let references to plain var references
-  standardiseLets(declarators);
+  standardizeLets(declarators);
 
   var state = {
     letReferences: this.letReferences,
@@ -292,7 +296,7 @@ LetScoping.prototype.getLetReferences = function () {
 
   // traverse through this block, stopping on functions and checking if they
   // contain any local let references
-  traverse(this.block, letReferenceBlockVisitor, this.scope, state);
+  this.scope.traverse(this.block, letReferenceBlockVisitor, state);
 
   return state.closurify;
 };
@@ -311,7 +315,7 @@ var loopVisitor = {
 
     if (t.isLoop(node)) {
       state.ignoreLabeless = true;
-      traverse(node, loopVisitor, scope, state);
+      scope.traverse(node, loopVisitor, state);
       state.ignoreLabeless = false;
     }
 
@@ -374,7 +378,7 @@ var loopLabelVisitor = {
  * @returns {Object}
  */
 
-LetScoping.prototype.checkLoop = function () {
+BlockScoping.prototype.checkLoop = function () {
   var state = {
     hasBreakContinue: false,
     ignoreLabeless:   false,
@@ -384,8 +388,8 @@ LetScoping.prototype.checkLoop = function () {
     map:              {}
   };
 
-  traverse(this.block, loopLabelVisitor, this.scope, state);
-  traverse(this.block, loopVisitor, this.scope, state);
+  this.scope.traverse(this.block, loopLabelVisitor, state);
+  this.scope.traverse(this.block, loopVisitor, state);
 
   return state;
 };
@@ -413,7 +417,7 @@ var hoistVarDeclarationsVisitor = {
  * once we wrap everything in a closure.
  */
 
-LetScoping.prototype.hoistVarDeclarations = function () {
+BlockScoping.prototype.hoistVarDeclarations = function () {
   traverse(this.block, hoistVarDeclarationsVisitor, this.scope, this);
 };
 
@@ -425,7 +429,7 @@ LetScoping.prototype.hoistVarDeclarations = function () {
  * @returns {Array}
  */
 
-LetScoping.prototype.pushDeclar = function (node) {
+BlockScoping.prototype.pushDeclar = function (node) {
   this.body.push(t.variableDeclaration(node.kind, node.declarations.map(function (declar) {
     return t.variableDeclarator(declar.id);
   })));
@@ -450,7 +454,7 @@ LetScoping.prototype.pushDeclar = function (node) {
  * @param {Node} call CallExpression
  */
 
-LetScoping.prototype.build = function (ret, call) {
+BlockScoping.prototype.build = function (ret, call) {
   var has = this.has;
   if (has.hasReturn || has.hasBreakContinue) {
     this.buildHas(ret, call);
@@ -466,7 +470,7 @@ LetScoping.prototype.build = function (ret, call) {
  * @param {Node} call CallExpression
  */
 
-LetScoping.prototype.buildHas = function (ret, call) {
+BlockScoping.prototype.buildHas = function (ret, call) {
   var body = this.body;
 
   body.push(t.variableDeclaration("var", [

lib/6to5/transformation/transformers/es6/classes.js

@@ -2,9 +2,12 @@
 
 var ReplaceSupers = require("../../helpers/replace-supers");
 var nameMethod    = require("../../helpers/name-method");
+var defineMap     = require("../../helpers/define-map");
 var util          = require("../../../util");
 var t             = require("../../../types");
 
+exports.check = t.isClass;
+
 exports.ClassDeclaration = function (node, parent, scope, context, file) {
   return new Class(node, file, scope, true).run();
 };
@@ -47,7 +50,8 @@ function Class(node, file, scope, isStatement) {
   this.staticMutatorMap   = {};
   this.hasConstructor     = false;
   this.className          = node.id || scope.generateUidIdentifier("class");
-  this.superName          = node.superClass;
+  this.superName          = node.superClass || t.identifier("Function");
+  this.hasSuper           = !!node.superClass;
   this.isLoose            = file.isLoose("es6.classes");
 }
 
@@ -66,12 +70,19 @@ Class.prototype.run = function () {
 
   var body = this.body = [];
 
+  var constructorBody = t.blockStatement([
+    t.expressionStatement(t.callExpression(file.addHelper("class-call-check"), [
+      t.thisExpression(),
+      className
+    ]))
+  ]);
   var constructor;
+
   if (this.node.id) {
-    constructor = t.functionDeclaration(className, [], t.blockStatement([]));
+    constructor = t.functionDeclaration(className, [], constructorBody);
     body.push(constructor);
   } else {
-    constructor = t.functionExpression(null, [], t.blockStatement([]));
+    constructor = t.functionExpression(null, [], constructorBody);
     body.push(t.variableDeclaration("var", [
       t.variableDeclarator(className, constructor)
     ]));
@@ -83,7 +94,7 @@ Class.prototype.run = function () {
 
   //
 
-  if (superName) {
+  if (this.hasSuper) {
     closureArgs.push(superName);
 
     if (!t.isIdentifier(superName)) {
@@ -159,11 +170,10 @@ Class.prototype.buildBody = function () {
   }
 
   // we have no constructor, we have a super, and the super doesn't appear to be falsy
-  if (!this.hasConstructor && superName && !t.isFalsyExpression(superName)) {
-    var defaultConstructorTemplate = "class-super-constructor-call";
-    if (this.isLoose) defaultConstructorTemplate += "-loose";
-
-    constructor.body.body.push(util.template(defaultConstructorTemplate, {
+  if (!this.hasConstructor && this.hasSuper && !t.isFalsyExpression(superName)) {
+    var helperName = "class-super-constructor-call";
+    if (this.isLoose) helperName += "-loose";
+    constructor.body.body.push(util.template(helperName, {
       CLASS_NAME: className,
       SUPER_NAME: this.superName
     }, true));
@@ -173,11 +183,11 @@ Class.prototype.buildBody = function () {
   var staticProps;
 
   if (this.hasInstanceMutators) {
-    instanceProps = util.buildDefineProperties(this.instanceMutatorMap);
+    instanceProps = defineMap.build(this.instanceMutatorMap);
   }
 
   if (this.hasStaticMutators) {
-    staticProps = util.buildDefineProperties(this.staticMutatorMap);
+    staticProps = defineMap.build(this.staticMutatorMap);
   }
 
   if (instanceProps || staticProps) {
@@ -230,8 +240,8 @@ Class.prototype.pushMethod = function (node) {
     this.hasInstanceMutators = true;
   }
 
-  util.pushMutatorMap(mutatorMap, methodName, kind, node.computed, node);
-  util.pushMutatorMap(mutatorMap, methodName, "enumerable", node.computed, false);
+  defineMap.push(mutatorMap, methodName, kind, node.computed, node);
+  defineMap.push(mutatorMap, methodName, "enumerable", node.computed, false);
 };
 
 /**
@@ -255,5 +265,5 @@ Class.prototype.pushConstructor = function (method) {
 
   construct._ignoreUserWhitespace = true;
   construct.params                = fn.params;
-  construct.body                  = fn.body;
+  construct.body.body             = construct.body.body.concat(fn.body.body);
 };

lib/6to5/transformation/transformers/es6/constants.js

@@ -1,12 +1,15 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
+
+exports.check = function (node) {
+  return t.isVariableDeclaration(node, { kind: "const" });
+};
 
 var visitor = {
   enter: function (node, parent, scope, context, state) {
-    if (t.isDeclaration(node) || t.isAssignmentExpression(node)) {
-      var ids = t.getDeclarations(node);
+    if (t.isAssignmentExpression(node) || t.isUpdateExpression(node)) {
+      var ids = t.getBindingIdentifiers(node);
 
       for (var key in ids) {
         var id = ids[key];
@@ -21,6 +24,9 @@ var visitor = {
         // constant so we can just ignore it
         if (id === constant) continue;
 
+        var localBinding = scope.getBinding(key);
+        if (localBinding !== constant) continue;
+
         throw state.file.errorWithNode(id, key + " is read-only");
       }
     } else if (t.isScope(node)) {
@@ -30,7 +36,7 @@ var visitor = {
 };
 
 exports.Scope = function (node, parent, scope, context, file) {
-  traverse(node, visitor, scope, {
+  scope.traverse(node, visitor, {
     constants: scope.getAllDeclarationsOfKind("const"),
     file:      file
   });

lib/6to5/transformation/transformers/es6/destructuring.js

@@ -1,11 +1,20 @@
 "use strict";
 
-// TODO: Clean up
-
 var t = require("../../../types");
 
-var buildVariableAssign = function (opts, id, init) {
-  var op = opts.operator;
+exports.check = t.isPattern;
+
+function Destructuring(opts) {
+  this.blockHoist = opts.blockHoist;
+  this.operator   = opts.operator;
+  this.nodes      = opts.nodes;
+  this.scope      = opts.scope;
+  this.file       = opts.file;
+  this.kind       = opts.kind;
+}
+
+Destructuring.prototype.buildVariableAssignment = function (id, init) {
+  var op = this.operator;
   if (t.isMemberExpression(id)) op = "=";
 
   var node;
@@ -13,47 +22,46 @@ var buildVariableAssign = function (opts, id, init) {
   if (op) {
     node = t.expressionStatement(t.assignmentExpression(op, id, init));
   } else {
-    node = t.variableDeclaration(opts.kind, [
+    node = t.variableDeclaration(this.kind, [
       t.variableDeclarator(id, init)
     ]);
   }
 
-  node._blockHoist = opts.blockHoist;
+  node._blockHoist = this.blockHoist;
 
   return node;
 };
 
-var buildVariableDeclar = function (opts, id, init) {
+Destructuring.prototype.buildVariableDeclaration = function (id, init) {
   var declar = t.variableDeclaration("var", [
     t.variableDeclarator(id, init)
   ]);
-  declar._blockHoist = opts.blockHoist;
+  declar._blockHoist = this.blockHoist;
   return declar;
 };
 
-var push = function (opts, nodes, elem, parentId) {
+Destructuring.prototype.push = function (elem, parentId) {
   if (t.isObjectPattern(elem)) {
-    pushObjectPattern(opts, nodes, elem, parentId);
+    this.pushObjectPattern(elem, parentId);
   } else if (t.isArrayPattern(elem)) {
-    pushArrayPattern(opts, nodes, elem, parentId);
+    this.pushArrayPattern(elem, parentId);
   } else if (t.isAssignmentPattern(elem)) {
-    pushAssignmentPattern(opts, nodes, elem, parentId);
+    this.pushAssignmentPattern(elem, parentId);
   } else {
-    nodes.push(buildVariableAssign(opts, elem, parentId));
+    this.nodes.push(this.buildVariableAssignment(elem, parentId));
   }
 };
 
-var pushAssignmentPattern = function (opts, nodes, pattern, parentId) {
-  var tempParentId = opts.scope.generateUidBasedOnNode(parentId, opts.file);
+Destructuring.prototype.pushAssignmentPattern = function (pattern, parentId) {
+  var tempParentId = this.scope.generateUidBasedOnNode(parentId);
 
   var declar = t.variableDeclaration("var", [
     t.variableDeclarator(tempParentId, parentId)
   ]);
-  declar._blockHoist = opts.blockHoist;
-  nodes.push(declar);
+  declar._blockHoist = this.blockHoist;
+  this.nodes.push(declar);
 
-  nodes.push(buildVariableAssign(
-    opts,
+  this.nodes.push(this.buildVariableAssignment(
     pattern.left,
     t.conditionalExpression(
       t.binaryExpression("===", tempParentId, t.identifier("undefined")),
@@ -63,72 +71,88 @@ var pushAssignmentPattern = function (opts, nodes, pattern, parentId) {
   ));
 };
 
-var pushObjectPattern = function (opts, nodes, pattern, parentId) {
+Destructuring.prototype.pushObjectSpread = function (pattern, parentId, prop, i) {
+  // get all the keys that appear in this object before the current spread
+  var keys = [];
+  for (var i2 = 0; i2 < pattern.properties.length; i2++) {
+    var prop2 = pattern.properties[i2];
+
+    if (i2 >= i) break;
+    if (t.isSpreadProperty(prop2)) continue;
+
+    var key = prop2.key;
+    if (t.isIdentifier(key)) {
+      key = t.literal(prop2.key.name);
+    }
+    keys.push(key);
+  }
+  keys = t.arrayExpression(keys);
+
+  var value = t.callExpression(this.file.addHelper("object-without-properties"), [parentId, keys]);
+  this.nodes.push(this.buildVariableAssignment(prop.argument, value));
+};
+
+Destructuring.prototype.pushObjectProperty = function (prop, parentId) {
+  if (t.isLiteral(prop.key)) prop.computed = true;
+
+  var pattern2   = prop.value;
+  var patternId2 = t.memberExpression(parentId, prop.key, prop.computed);
+
+  if (t.isPattern(pattern2)) {
+    this.push(pattern2, patternId2);
+  } else {
+    this.nodes.push(this.buildVariableAssignment(pattern2, patternId2));
+  }
+};
+
+Destructuring.prototype.pushObjectPattern = function (pattern, parentId) {
+  if (!pattern.properties.length) {
+    this.nodes.push(t.expressionStatement(
+      t.callExpression(this.file.addHelper("object-destructuring-empty"), [parentId])
+    ));
+  }
+
   for (var i = 0; i < pattern.properties.length; i++) {
     var prop = pattern.properties[i];
     if (t.isSpreadProperty(prop)) {
-      // get all the keys that appear in this object before the current spread
-      var keys = [];
-      for (var i2 = 0; i2 < pattern.properties.length; i2++) {
-        var prop2 = pattern.properties[i2];
-
-        if (i2 >= i) break;
-        if (t.isSpreadProperty(prop2)) continue;
-
-        var key = prop2.key;
-        if (t.isIdentifier(key)) {
-          key = t.literal(prop2.key.name);
-        }
-        keys.push(key);
-      }
-      keys = t.arrayExpression(keys);
-
-      var value = t.callExpression(opts.file.addHelper("object-without-properties"), [parentId, keys]);
-      nodes.push(buildVariableAssign(opts, prop.argument, value));
+      this.pushObjectSpread(pattern, parentId, prop, i);
     } else {
-      if (t.isLiteral(prop.key)) prop.computed = true;
-
-      var pattern2   = prop.value;
-      var patternId2 = t.memberExpression(parentId, prop.key, prop.computed);
-
-      if (t.isPattern(pattern2)) {
-        push(opts, nodes, pattern2, patternId2);
-      } else {
-        nodes.push(buildVariableAssign(opts, pattern2, patternId2));
-      }
+      this.pushObjectProperty(prop, parentId);
     }
   }
 };
 
-var pushArrayPattern = function (opts, nodes, pattern, parentId) {
-  if (!pattern.elements) return;
-
-  var i;
-
-  var hasRest = false;
-  for (i = 0; i < pattern.elements.length; i++) {
+var hasRest = function (pattern) {
+  for (var i = 0; i < pattern.elements.length; i++) {
     if (t.isRestElement(pattern.elements[i])) {
-      hasRest = true;
-      break;
+      return true;
     }
   }
+  return false;
+};
 
-  var toArray = opts.file.toArray(parentId, !hasRest && pattern.elements.length);
+Destructuring.prototype.pushArrayPattern = function (pattern, parentId) {
+  if (!pattern.elements) return;
 
-  var _parentId = opts.scope.generateUidBasedOnNode(parentId, opts.file);
-  nodes.push(buildVariableDeclar(opts, _parentId, toArray));
+  // if we have a rest then we need all the elements
+  var count = !hasRest(pattern) && pattern.elements.length;
+
+  var toArray = this.file.toArray(parentId, count);
+
+  var _parentId = this.scope.generateUidBasedOnNode(parentId, this.file);
+  this.nodes.push(this.buildVariableDeclaration(_parentId, toArray));
   parentId = _parentId;
 
-  for (i = 0; i < pattern.elements.length; i++) {
+  for (var i = 0; i < pattern.elements.length; i++) {
     var elem = pattern.elements[i];
-    if (!elem) continue;
 
-    i = +i;
+    // hole
+    if (!elem) continue;
 
     var newPatternId;
 
     if (t.isRestElement(elem)) {
-      newPatternId = opts.file.toArray(parentId);
+      newPatternId = this.file.toArray(parentId);
 
       if (i > 0) {
         newPatternId = t.callExpression(t.memberExpression(newPatternId, t.identifier("slice")), [t.literal(i)]);
@@ -139,23 +163,18 @@ var pushArrayPattern = function (opts, nodes, pattern, parentId) {
       newPatternId = t.memberExpression(parentId, t.literal(i), true);
     }
 
-    push(opts, nodes, elem, newPatternId);
+    this.push(elem, newPatternId);
   }
 };
 
-var pushPattern = function (opts) {
-  var nodes = opts.nodes;
-  var pattern = opts.pattern;
-  var parentId = opts.id;
-  var scope = opts.scope;
-
+Destructuring.prototype.init = function (pattern, parentId) {
   if (!t.isArrayExpression(parentId) && !t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
-    var key = scope.generateUidBasedOnNode(parentId);
-    nodes.push(buildVariableDeclar(opts, key, parentId));
+    var key = this.scope.generateUidBasedOnNode(parentId);
+    this.nodes.push(this.buildVariableDeclaration(key, parentId));
     parentId = key;
   }
 
-  push(opts, nodes, pattern, parentId);
+  this.push(pattern, parentId);
 };
 
 exports.ForInStatement =
@@ -173,11 +192,14 @@ exports.ForOfStatement = function (node, parent, scope, context, file) {
 
   var nodes = [];
 
-  push({
+  var destructuring = new Destructuring({
     kind: declar.kind,
     file: file,
-    scope: scope
-  }, nodes, pattern, key);
+    scope: scope,
+    nodes: nodes
+  });
+
+  destructuring.init(pattern, key);
 
   t.ensureBlock(node);
 
@@ -196,15 +218,14 @@ exports.Function = function (node, parent, scope, context, file) {
     hasDestructuring = true;
     var parentId = scope.generateUidIdentifier("ref");
 
-    pushPattern({
+    var destructuring = new Destructuring({
       blockHoist: node.params.length - i,
-      pattern:    pattern,
       nodes:      nodes,
       scope:      scope,
       file:       file,
       kind:       "var",
-      id:         parentId
     });
+    destructuring.init(pattern, parentId);
 
     return parentId;
   });
@@ -226,11 +247,13 @@ exports.CatchClause = function (node, parent, scope, context, file) {
 
   var nodes = [];
 
-  push({
+  var destructuring = new Destructuring({
     kind: "var",
     file: file,
-    scope: scope
-  }, nodes, pattern, ref);
+    scope: scope,
+    nodes: nodes
+  });
+  destructuring.init(pattern, ref);
 
   node.body.body = nodes.concat(node.body.body);
 };
@@ -248,11 +271,13 @@ exports.ExpressionStatement = function (node, parent, scope, context, file) {
     t.variableDeclarator(ref, expr.right)
   ]));
 
-  push({
+  var destructuring = new Destructuring({
     operator: expr.operator,
     file: file,
-    scope: scope
-  }, nodes, expr.left, ref);
+    scope: scope,
+    nodes: nodes
+  });
+  destructuring.init(expr.left, ref);
 
   return nodes;
 };
@@ -269,50 +294,50 @@ exports.AssignmentExpression = function (node, parent, scope, context, file) {
   var nodes = [];
   nodes.push(t.assignmentExpression("=", ref, node.right));
 
-  push({
+  var destructuring = new Destructuring({
     operator: node.operator,
     file: file,
-    scope: scope
-  }, nodes, node.left, ref);
+    scope: scope,
+    nodes: nodes
+  });
+  destructuring.init(node.left, ref);
 
   nodes.push(ref);
 
   return t.toSequenceExpression(nodes, scope);
 };
 
-exports.VariableDeclaration = function (node, parent, scope, context, file) {
-  if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
-
-  var nodes = [];
-  var i;
-  var declar;
-
-  var hasPattern = false;
-  for (i = 0; i < node.declarations.length; i++) {
-    declar = node.declarations[i];
-    if (t.isPattern(declar.id)) {
-      hasPattern = true;
-      break;
+var variableDeclarationhasPattern = function (node) {
+  for (var i = 0; i < node.declarations.length; i++) {
+    if (t.isPattern(node.declarations[i].id)) {
+      return true;
     }
   }
-  if (!hasPattern) return;
+  return false;
+};
 
-  for (i = 0; i < node.declarations.length; i++) {
+exports.VariableDeclaration = function (node, parent, scope, context, file) {
+  if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
+  if (!variableDeclarationhasPattern(node)) return;
+
+  var nodes = [];
+  var declar;
+
+  for (var i = 0; i < node.declarations.length; i++) {
     declar = node.declarations[i];
 
     var patternId = declar.init;
     var pattern   = declar.id;
-    var opts = {
-      pattern: pattern,
-      nodes:   nodes,
-      scope:   scope,
-      kind:    node.kind,
-      file:    file,
-      id:      patternId,
-    };
+
+    var destructuring = new Destructuring({
+      nodes: nodes,
+      scope: scope,
+      kind:  node.kind,
+      file:  file
+    });
 
     if (t.isPattern(pattern) && patternId) {
-      pushPattern(opts);
+      destructuring.init(pattern, patternId);
 
       if (+i !== node.declarations.length - 1) {
         // we aren't the last declarator so let's just make the
@@ -320,11 +345,14 @@ exports.VariableDeclaration = function (node, parent, scope, context, file) {
         t.inherits(nodes[nodes.length - 1], declar);
       }
     } else {
-      nodes.push(t.inherits(buildVariableAssign(opts, declar.id, declar.init), declar));
+      nodes.push(t.inherits(destructuring.buildVariableAssignment(declar.id, declar.init), declar));
     }
   }
 
   if (!t.isProgram(parent) && !t.isBlockStatement(parent)) {
+    // https://github.com/6to5/6to5/issues/113
+    // for (let [x] = [0]; false;) {}
+
     declar = null;
 
     for (i = 0; i < nodes.length; i++) {

lib/6to5/transformation/transformers/es6/for-of.js

@@ -3,6 +3,8 @@
 var util = require("../../../util");
 var t    = require("../../../types");
 
+exports.check = t.isForOfStatement;
+
 exports.ForOfStatement = function (node, parent, scope, context, file) {
   var callback = spec;
   if (file.isLoose("es6.forOf")) callback = loose;

lib/6to5/transformation/transformers/es6/modules.js

@@ -2,6 +2,8 @@
 
 var t = require("../../../types");
 
+exports.check = require("../internal/modules").check;
+
 exports.ImportDeclaration = function (node, parent, scope, context, file) {
   var nodes = [];
 
@@ -26,7 +28,7 @@ exports.ExportDeclaration = function (node, parent, scope, context, file) {
   var i;
 
   if (node.declaration) {
-    // make sure variable exports have an initialiser
+    // make sure variable exports have an initializer
     // this is done here to avoid duplicating it in the module formatters
     if (t.isVariableDeclaration(node.declaration)) {
       var declar = node.declaration.declarations[0];

lib/6to5/transformation/transformers/es6/parameters.default.js

@@ -1,8 +1,11 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var util     = require("../../../util");
-var t        = require("../../../types");
+var util = require("../../../util");
+var t    = require("../../../types");
+
+exports.check = function (node) {
+  return t.isFunction(node) && hasDefaults(node);
+};
 
 var hasDefaults = function (node) {
   for (var i = 0; i < node.params.length; i++) {
@@ -13,7 +16,7 @@ var hasDefaults = function (node) {
 
 var iifeVisitor = {
   enter: function (node, parent, scope, context, state) {
-    if (t.isReferencedIdentifier(node, parent) && state.scope.hasOwn(node.name)) {
+    if (t.isReferencedIdentifier(node, parent) && state.scope.hasOwnReference(node.name)) {
       state.iife = true;
       context.stop();
     }
@@ -48,10 +51,10 @@ exports.Function = function (node, parent, scope) {
     node.params[i] = scope.generateUidIdentifier("x");
 
     if (!state.iife) {
-      if (t.isIdentifier(right) && scope.hasOwn(right.name)) {
+      if (t.isIdentifier(right) && scope.hasOwnReference(right.name)) {
         state.iife = true;
       } else {
-        traverse(right, iifeVisitor, scope, state);
+        scope.traverse(right, iifeVisitor, state);
       }
     }
 

lib/6to5/transformation/transformers/es6/parameters.rest.js

@@ -3,6 +3,8 @@
 var util = require("../../../util");
 var t    = require("../../../types");
 
+exports.check = t.isRestElement;
+
 var hasRest = function (node) {
   return t.isRestElement(node.params[node.params.length - 1]);
 };

lib/6to5/transformation/transformers/es6/properties.computed.js

@@ -2,6 +2,10 @@
 
 var t = require("../../../types");
 
+exports.check = function (node) {
+  return t.isProperty(node) && node.computed;
+};
+
 exports.ObjectExpression = function (node, parent, scope, context, file) {
   var hasComputed = false;
 
@@ -58,7 +62,7 @@ var spec = function (node, body, objId, initProps, file) {
   var props = node.properties;
   var prop, key;
 
-  // normalise key
+  // normalize key
 
   for (var i = 0; i < props.length; i++) {
     prop = props[i];

lib/6to5/transformation/transformers/es6/properties.shorthand.js

@@ -4,6 +4,10 @@ var nameMethod = require("../../helpers/name-method");
 var t          = require("../../../types");
 var clone      = require("lodash/lang/clone");
 
+exports.check = function (node) {
+  return t.isProperty(node) && (node.method || node.shorthand);
+};
+
 exports.Property = function (node, parent, scope, context, file) {
   if (node.method) {
     node.method = false;

lib/6to5/transformation/transformers/es6/spread.js

@@ -1,7 +1,9 @@
 "use strict";
 
-var t = require("../../../types");
 var contains = require("lodash/collection/contains");
+var t        = require("../../../types");
+
+exports.check = t.isSpreadElement;
 
 var getSpreadLiteral = function (spread, file) {
   return file.toArray(spread.argument);

lib/6to5/transformation/transformers/es6/template-literals.js

@@ -6,6 +6,10 @@ var buildBinaryExpression = function (left, right) {
   return t.binaryExpression("+", left, right);
 };
 
+exports.check = function (node) {
+  return t.isTemplateLiteral(node) || t.isTaggedTemplateExpression(node);
+};
+
 exports.TaggedTemplateExpression = function (node, parent, scope, context, file) {
   var args = [];
   var quasi = node.quasi;

lib/6to5/transformation/transformers/es6/unicode-regex.js

@@ -2,6 +2,11 @@
 
 var rewritePattern = require("regexpu/rewrite-pattern");
 var pull           = require("lodash/array/pull");
+var t              = require("../../../types");
+
+exports.check = function (node) {
+  return t.isLiteral(node) && node.regex && node.regex.flags.indexOf("u") >= 0;
+};
 
 exports.Literal = function (node) {
   var regex = node.regex;

lib/6to5/transformation/transformers/es7/object-rest-spread.js

@@ -6,18 +6,21 @@ var t = require("../../../types");
 
 exports.experimental = true;
 
-exports.ObjectExpression = function (node, parent, scope, context, file) {
-  var hasSpread = false;
-  var i;
-  var prop;
-  for (i = 0; i < node.properties.length; i++) {
-    prop = node.properties[i];
-    if (t.isSpreadProperty(prop)) {
-      hasSpread = true;
-      break;
+exports.manipulateOptions = function (opts) {
+  if (opts.whitelist.length) opts.whitelist.push("es6.destructuring");
+};
+
+var hasSpread = function (node) {
+  for (var i = 0; i < node.properties.length; i++) {
+    if (t.isSpreadProperty(node.properties[i])) {
+      return true;
     }
   }
-  if (!hasSpread) return;
+  return false;
+};
+
+exports.ObjectExpression = function (node, parent, scope, context, file) {
+  if (!hasSpread(node)) return;
 
   var args = [];
   var props = [];
@@ -28,8 +31,8 @@ exports.ObjectExpression = function (node, parent, scope, context, file) {
     props = [];
   };
 
-  for (i = 0; i < node.properties.length; i++) {
-    prop = node.properties[i];
+  for (var i = 0; i < node.properties.length; i++) {
+    var prop = node.properties[i];
     if (t.isSpreadProperty(prop)) {
       push();
       args.push(prop.argument);

lib/6to5/transformation/transformers/index.js

@@ -27,7 +27,7 @@ module.exports = {
   asyncToGenerator:                        require("./other/async-to-generator"),
   bluebirdCoroutines:                      require("./other/bluebird-coroutines"),
 
-  "es7.objectSpread":                      require("./es7/object-spread"),
+  "es7.objectRestSpread":                  require("./es7/object-rest-spread"),
   "es7.exponentiationOperator":            require("./es7/exponentiation-operator"),
   "es6.spread":                            require("./es6/spread"),
   "es6.templateLiterals":                  require("./es6/template-literals"),
@@ -80,5 +80,10 @@ module.exports = {
   "spec.undefinedToVoid":                  require("./spec/undefined-to-void"),
 
   "minification.propertyLiterals":         require("./minification/property-literals"),
-  "minification.memberExpressionLiterals": require("./minification/member-expression-literals")
+  "minification.memberExpressionLiterals": require("./minification/member-expression-literals"),
+
+  "minification.removeDebugger":           require("./minification/remove-debugger"),
+  "minification.removeConsoleCalls":       require("./minification/remove-console-calls"),
+  "minification.deadCodeElimination":      require("./minification/dead-code-elimination"),
+  "minification.renameLocalVariables":     require("./minification/rename-local-variables")
 };

lib/6to5/transformation/transformers/internal/alias-functions.js

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
 
 var functionChildrenVisitor = {
   enter: function (node, parent, scope, context, state) {
@@ -37,7 +36,7 @@ var functionVisitor = {
     }
 
     // traverse all child nodes of this function and find `arguments` and `this`
-    traverse(node, functionChildrenVisitor, scope, state);
+    scope.traverse(node, functionChildrenVisitor, state);
 
     return context.skip();
   }
@@ -58,7 +57,7 @@ var go = function (getBody, node, scope) {
 
   // traverse the function and find all alias functions so we can alias
   // `arguments` and `this` if necessary
-  traverse(node, functionVisitor, scope, state);
+  scope.traverse(node, functionVisitor, state);
 
   var body;
 

lib/6to5/transformation/transformers/internal/modules.js

@@ -15,6 +15,10 @@ var resolveModuleSource = function (node, parent, scope, context, file) {
   }
 };
 
+exports.check = function (node) {
+  return t.isImportDeclaration(node) || t.isExportDeclaration(node);
+};
+
 exports.ImportDeclaration = resolveModuleSource;
 
 exports.ExportDeclaration = function (node, parent, scope) {

lib/6to5/transformation/transformers/minification/dead-code-elimination.js

@@ -0,0 +1,77 @@
+var t = require("../../../types");
+
+exports.optional = true;
+
+exports.ExpressionStatement = function (node, parent, scope, context) {
+  // remove consequenceless expressions such as local variables and literals
+  //
+  //   var foo = true; foo; -> var foo = true;
+  //   "foo"; ->
+  //
+
+  var expr = node.expression;
+  if (t.isLiteral(expr) || (t.isIdentifier(node) && t.hasBinding(node.name))) {
+    context.remove();
+  }
+};
+
+exports.IfStatement = {
+  exit: function (node, parent, scope, context) {
+    // todo: in scenarios where we can just return the consequent or
+    // alternate we should drop the block statement if it contains no
+    // block scoped variables
+
+    var consequent = node.consequent;
+    var alternate  = node.alternate;
+    var test       = node.test;
+
+    // we can check if a test will be truthy 100% and if so we can inline
+    // the consequent and completely ignore the alternate
+    //
+    //   if (true) { foo; } -> { foo; }
+    //   if ("foo") { foo; } -> { foo; }
+    //
+
+    if (t.isLiteral(test) && test.value) {
+      return alternate;
+    }
+
+    // we can check if a test will be falsy 100% and if so we can inline
+    // the alternate if there is one and completely remove the consequent
+    //
+    //   if ("") { bar; } else { foo; } -> { foo; }
+    //   if ("") { bar; } ->
+    //
+
+    if (t.isFalsyExpression(test)) {
+      if (alternate) {
+        return alternate;
+      } else {
+        return context.remove();
+      }
+    }
+
+    // remove alternate blocks that are empty
+    //
+    //   if (foo) { foo; } else {} -> if (foo) { foo; }
+    //
+
+    if (t.isBlockStatement(alternate) && !alternate.body.length) {
+      alternate = node.alternate = null;
+    }
+
+    // turn alternate blocks into a consequent and flip the test if the
+    // consequent block is empty
+    //
+    //   if (foo) {} else { bar; }
+    //   if (!foo) { bar; }
+    //
+
+    if (t.blockStatement(consequent) && !consequent.body.length &&
+        t.isBlockStatement(alternate) && alternate.body.length) {
+      node.consequent = node.alternate;
+      node.alternate  = null;
+      node.test       = t.unaryExpression("!", test, true);
+    }
+  }
+};

lib/6to5/transformation/transformers/minification/remove-console-calls.js

@@ -0,0 +1,13 @@
+"use strict";
+
+var t = require("../../../types");
+
+var isConsole = t.buildMatchMemberExpression("console", true);
+
+exports.optional = true;
+
+exports.CallExpression = function (node, parent, scope, context) {
+  if (isConsole(node.callee)) {
+    context.remove();
+  }
+};

lib/6to5/transformation/transformers/minification/remove-debugger.js

@@ -0,0 +1,9 @@
+var t = require("../../../types");
+
+exports.optional = true;
+
+exports.ExpressionStatement = function (node, parent, scope, context) {
+  if (t.isIdentifier(node.expression, { name: "debugger" })) {
+    context.remove();
+  }
+};

lib/6to5/transformation/transformers/minification/rename-local-variables.js

@@ -0,0 +1,10 @@
+//var t = require("../../../types");
+
+exports.optional = true;
+
+exports.Scope = function () {
+  // todo: get all binding identifiers, generate compact names
+  // that wont collide and then call the remap identifier helper
+  // this transformer **has** to be ran last as it will absolutley
+  // destroy the scope tree
+};

lib/6to5/transformation/transformers/other/react.js

@@ -5,9 +5,16 @@
 
 // jsx
 
-var esutils = require("esutils");
-var react   = require("../../helpers/react");
-var t       = require("../../../types");
+var isString = require("lodash/lang/isString");
+var esutils  = require("esutils");
+var react    = require("../../helpers/react");
+var t        = require("../../../types");
+
+exports.check = function (node) {
+  if (t.isJSX(node)) return true;
+  if (react.isCreateClass(node)) return true;
+  return false;
+};
 
 exports.JSXIdentifier = function (node, parent) {
   if (node.name === "this" && t.isReferenced(node, parent)) {
@@ -160,6 +167,8 @@ exports.JSXElement = {
       callExpr.arguments.push(child);
     }
 
+    callExpr.arguments = flatten(callExpr.arguments);
+
     if (callExpr.arguments.length >= 3) {
       callExpr._prettyCall = true;
     }
@@ -168,14 +177,45 @@ exports.JSXElement = {
   }
 };
 
+var isStringLiteral = function (node) {
+  return t.isLiteral(node) && isString(node.value);
+};
+
+var flatten = function (args) {
+  var flattened = [];
+  var last;
+
+  for (var i = 0; i < args.length; i++) {
+    var arg = args[i];
+    if (isStringLiteral(arg) && isStringLiteral(last)) {
+      last.value += arg.value;
+    } else {
+      last = arg;
+      flattened.push(arg);
+    }
+  }
+
+  return flattened;
+};
+
 var cleanJSXElementLiteralChild = function (child, args) {
   var lines = child.value.split(/\r\n|\n|\r/);
 
-  for (var i = 0; i < lines.length; i++) {
+  var lastNonEmptyLine = 0;
+  var i;
+
+  for (i = 0; i < lines.length; i++) {
+    if (lines[i].match(/[^ \t]/)) {
+      lastNonEmptyLine = i;
+    }
+  }
+
+  for (i = 0; i < lines.length; i++) {
     var line = lines[i];
 
     var isFirstLine = i === 0;
     var isLastLine = i === lines.length - 1;
+    var isLastNonEmptyLine = i === lastNonEmptyLine;
 
     // replace rendered whitespace tabs with spaces
     var trimmedLine = line.replace(/\t/g, " ");
@@ -191,6 +231,10 @@ var cleanJSXElementLiteralChild = function (child, args) {
     }
 
     if (trimmedLine) {
+      if (!isLastNonEmptyLine) {
+        trimmedLine += " ";
+      }
+
       args.push(t.literal(trimmedLine));
     }
   }
@@ -199,8 +243,6 @@ var cleanJSXElementLiteralChild = function (child, args) {
 // display names
 
 var addDisplayName = function (id, call) {
-  if (!react.isCreateClass(call)) return;
-
   var props = call.arguments[0].properties;
   var safe = true;
 
@@ -217,6 +259,12 @@ var addDisplayName = function (id, call) {
   }
 };
 
+exports.ExportDeclaration = function (node, parent, scope, context, file) {
+  if (node.default && react.isCreateClass(node.declaration)) {
+    addDisplayName(file.opts.basename, node.declaration);
+  }
+};
+
 exports.AssignmentExpression =
 exports.Property =
 exports.VariableDeclarator = function (node) {
@@ -237,7 +285,7 @@ exports.VariableDeclarator = function (node) {
     left = left.property;
   }
 
-  if (t.isIdentifier(left)) {
+  if (t.isIdentifier(left) && react.isCreateClass(right)) {
     addDisplayName(left.name, right);
   }
 };

lib/6to5/transformation/transformers/other/regenerator.js

@@ -1,6 +1,11 @@
 "use strict";
 
 var regenerator = require("regenerator-6to5");
+var t           = require("../../../types");
+
+exports.check = function (node) {
+  return t.isFunction(node) && (node.async || node.generator);
+};
 
 exports.ast = {
   before: function (ast, file) {

lib/6to5/transformation/transformers/other/self-contained.js

@@ -1,6 +1,5 @@
 "use strict";
 
-var traverse = require("../../../traverse");
 var util     = require("../../../util");
 var core     = require("core-js/library");
 var t        = require("../../../types");
@@ -31,11 +30,11 @@ var astVisitor = {
 
       if (!t.isReferenced(obj, node)) return;
 
-      if (!node.computed && coreHas(obj) && has(core[obj.name], prop.name)) {
+      if (!node.computed && coreHas(obj) && has(core[obj.name], prop.name) && !scope.getBinding(obj.name)) {
         context.skip();
         return t.prependToMemberExpression(node, file.get("coreIdentifier"));
       }
-    } else if (t.isReferencedIdentifier(node, parent) && !t.isMemberExpression(parent) && contains(ALIASABLE_CONSTRUCTORS, node.name) && !scope.get(node.name, true)) {
+    } else if (t.isReferencedIdentifier(node, parent) && !t.isMemberExpression(parent) && contains(ALIASABLE_CONSTRUCTORS, node.name) && !scope.getBinding(node.name)) {
       // Symbol() -> _core.Symbol(); new Promise -> new _core.Promise
       return t.memberExpression(file.get("coreIdentifier"), node);
     } else if (t.isCallExpression(node)) {
@@ -61,6 +60,10 @@ var astVisitor = {
 
 exports.optional = true;
 
+exports.manipulateOptions = function (opts) {
+  if (opts.whitelist.length) opts.whitelist.push("es6.modules");
+};
+
 exports.ast = {
   enter: function (ast, file) {
     file.setDynamic("runtimeIdentifier", function () {
@@ -77,7 +80,7 @@ exports.ast = {
   },
 
   after: function (ast, file) {
-    traverse(ast, astVisitor, null, file);
+    file.scope.traverse(ast, astVisitor, file);
   }
 };
 

lib/6to5/transformation/transformers/playground/object-getter-memoization.js

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
 
 exports.playground = true;
 
@@ -23,6 +22,7 @@ exports.Property =
 exports.MethodDefinition = function (node, parent, scope, context, file) {
   if (node.kind !== "memo") return;
   node.kind = "get";
+  file.checkNode(node, scope);
 
   var value = node.value;
   t.ensureBlock(value);
@@ -38,5 +38,5 @@ exports.MethodDefinition = function (node, parent, scope, context, file) {
     file: file
   };
 
-  traverse(value, visitor, scope, state);
+  scope.traverse(value, visitor, state);
 };

lib/6to5/transformation/transformers/validation/undeclared-variable-check.js

@@ -7,19 +7,19 @@ exports.optional = true;
 
 exports.Identifier = function (node, parent, scope, context, file) {
   if (!t.isReferenced(node, parent)) return;
-  if (scope.has(node.name, true)) return;
+  if (scope.hasBinding(node.name)) return;
 
   var msg = "Reference to undeclared variable";
 
   // get the closest declaration to offer as a suggestion
   // the variable name may have just been mistyped
 
-  var declarations = scope.getAllDeclarations();
+  var bindings = scope.getAllBindings();
 
   var closest;
   var shortest = -1;
 
-  for (var name in declarations) {
+  for (var name in bindings) {
     var distance = levenshtein(node.name, name);
     if (distance <= 0 || distance > 3) continue;
     if (distance <= shortest) continue;

lib/6to5/traverse/index.js

@@ -10,11 +10,12 @@ var contains = require("lodash/collection/contains");
 var flatten  = require("lodash/array/flatten");
 var compact  = require("lodash/array/compact");
 
-function TraversalContext() {
+function TraversalContext(scope) {
   this.shouldFlatten = false;
   this.shouldRemove  = false;
   this.shouldSkip    = false;
   this.shouldStop    = false;
+  this.scope         = scope;
 }
 
 TraversalContext.prototype.flatten = function () {
@@ -41,16 +42,34 @@ TraversalContext.prototype.reset = function () {
   this.shouldStop   = false;
 };
 
-function replaceNode(obj, key, node, result) {
-  var isArray = Array.isArray(result);
+TraversalContext.prototype.maybeRemove = function (obj, key) {
+  if (this.shouldRemove) {
+    obj[key] = null;
+    this.flatten();
+  }
+};
+
+TraversalContext.prototype.replaceNode = function (obj, key, node, replacement, scope) {
+  var isArray = Array.isArray(replacement);
 
   // inherit comments from original node to the first replacement node
-  var inheritTo = result;
-  if (isArray) inheritTo = result[0];
+  var inheritTo = replacement;
+  if (isArray) inheritTo = replacement[0];
   if (inheritTo) t.inheritsComments(inheritTo, node);
 
   // replace the node
-  obj[key] = result;
+  obj[key] = replacement;
+
+  var file = this.scope && this.scope.file;
+  if (file) {
+    if (isArray) {
+      for (var i = 0; i < replacement.length; i++) {
+        file.checkNode(replacement[i], scope);
+      }
+    } else {
+      file.checkNode(replacement, scope);
+    }
+  }
 
   // we're replacing a statement or block node with an array of statements so we better
   // ensure that it's a block
@@ -59,44 +78,20 @@ function replaceNode(obj, key, node, result) {
   }
 
   if (isArray) {
-    return true;
+    this.flatten();
   }
-}
-
-TraversalContext.prototype.enterNode = function (obj, key, node, enter, parent, scope, state) {
-  var result = enter(node, parent, scope, this, state);
-  var flatten = false;
-
-  if (result) {
-    flatten = replaceNode(obj, key, node, result);
-    node = result;
-
-    if (flatten) {
-      this.shouldFlatten = true;
-    }
-  }
-
-  if (this.shouldRemove) {
-    obj[key] = null;
-    this.shouldFlatten = true;
-  }
-
-  return node;
 };
 
-TraversalContext.prototype.exitNode = function (obj, key, node, exit, parent, scope, state) {
-  var result = exit(node, parent, scope, this, state);
-  var flatten = false;
+TraversalContext.prototype.call = function (fn, obj, key, node, parent, scope, state) {
+  var replacement = fn(node, parent, scope, this, state);
 
-  if (result) {
-    flatten = replaceNode(obj, key, node, result);
-    node = result;
-
-    if (flatten) {
-      this.shouldFlatten = true;
-    }
+  if (replacement) {
+    this.replaceNode(obj, key, node, replacement, scope);
+    node = replacement;
   }
 
+  this.maybeRemove(obj, key);
+
   return node;
 };
 
@@ -116,7 +111,7 @@ TraversalContext.prototype.visitNode = function (obj, key, opts, scope, parent,
     ourScope = new Scope(node, parent, scope);
   }
 
-  node = this.enterNode(obj, key, node, opts.enter, parent, ourScope, state);
+  node = this.call(opts.enter, obj, key, node, parent, ourScope, state);
 
   if (this.shouldSkip) {
     return this.shouldStop;
@@ -130,7 +125,7 @@ TraversalContext.prototype.visitNode = function (obj, key, opts, scope, parent,
     }
   } else {
     traverseNode(node, opts, ourScope, state);
-    this.exitNode(obj, key, node, opts.exit, parent, ourScope, state);
+    this.call(opts.exit, obj, key, node, parent, ourScope, state);
   }
 
   return this.shouldStop;
@@ -168,7 +163,7 @@ function traverseNode(node, opts, scope, state) {
   var keys = t.VISITOR_KEYS[node.type];
   if (!keys) return;
 
-  var context = new TraversalContext();
+  var context = new TraversalContext(scope);
   for (var i = 0; i < keys.length; i++) {
     if (context.visit(node, keys[i], opts, scope, state)) {
       return;

lib/6to5/traverse/scope.js

@@ -2,20 +2,19 @@
 
 module.exports = Scope;
 
+var contains = require("lodash/collection/contains");
 var traverse = require("./index");
+var defaults = require("lodash/object/defaults");
 var globals  = require("globals");
+var flatten  = require("lodash/array/flatten");
+var extend   = require("lodash/object/extend");
 var object   = require("../helpers/object");
-var t        = require("../types");
 var each     = require("lodash/collection/each");
 var has      = require("lodash/object/has");
-var contains = require("lodash/collection/contains");
-var flatten  = require("lodash/array/flatten");
-var defaults = require("lodash/object/defaults");
-
-var FOR_KEYS = ["left", "init"];
+var t        = require("../types");
 
 /**
- * This searches the current "scope" and collects all references/declarations
+ * This searches the current "scope" and collects all references/bindings
  * within.
  *
  * @param {Node} block
@@ -31,28 +30,21 @@ function Scope(block, parentBlock, parent, file) {
   this.parentBlock = parentBlock;
   this.block       = block;
 
-  var info = this.getInfo();
-  this.references = info.references;
-  this.declarations = info.declarations;
-  this.declarationKinds = info.declarationKinds;
+  this.crawl();
 }
 
 Scope.defaultDeclarations = flatten([globals.builtin, globals.browser, globals.node].map(Object.keys));
 
-Scope.prototype._add = function (node, references, throwOnDuplicate) {
-  if (!node) return;
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Object} opts
+ * @param [state]
+ */
 
-  var ids = t.getDeclarations(node);
-
-  for (var key in ids) {
-    var id = ids[key];
-
-    if (throwOnDuplicate && references[key]) {
-      throw this.file.errorWithNode(id, "Duplicate declaration", TypeError);
-    }
-
-    references[key] = id;
-  }
+Scope.prototype.traverse = function (node, opts, state) {
+  traverse(node, opts, this, state);
 };
 
 /**
@@ -130,7 +122,7 @@ Scope.prototype.generateUidBasedOnNode = function (parent) {
  */
 
 Scope.prototype.generateTempBasedOnNode = function (node) {
-  if (t.isIdentifier(node) && this.has(node.name, true)) {
+  if (t.isIdentifier(node) && this.hasBinding(node.name)) {
     return null;
   }
 
@@ -142,12 +134,91 @@ Scope.prototype.generateTempBasedOnNode = function (node) {
   return id;
 };
 
+Scope.prototype.checkBlockScopedCollisions = function (key, id) {
+  if (this.declarationKinds["let"][key] || this.declarationKinds["const"][key]) {
+    throw this.file.errorWithNode(id, "Duplicate declaration " + key, TypeError);
+  }
+};
+
+Scope.prototype.inferType = function (node) {
+  var target;
+
+  if (t.isVariableDeclarator(node)) {
+    target = node.init;
+  }
+
+  if (t.isLiteral(target) || t.isArrayExpression(target) || t.isObjectExpression(target)) {
+    // todo: possibly call some helper that will resolve these to a type annotation
+  }
+
+  if (t.isCallExpression(target)) {
+    // todo: need to resolve this to a return type
+  }
+
+  if (t.isMemberExpression(target)) {
+    // todo: crawl this and find the correct type, bail on anything that we cannot
+    // possibly be 100% confident on
+  }
+
+  if (t.isIdentifier(target)) {
+    return this.getType(target.name);
+  }
+};
+
+Scope.prototype.registerType = function (key, id, node) {
+  var type;
+
+  if (id.typeAnnotation) {
+    type = id.typeAnnotation;
+  }
+
+  if (!type) {
+    type = this.inferType(node);
+  }
+
+  if (type) {
+    if (t.isTypeAnnotation(type)) type = type.typeAnnotation;
+    this.types[key] = type;
+  }
+};
+
+Scope.prototype.register = function (node, reference, kind) {
+  if (t.isVariableDeclaration(node)) {
+    return this.registerVariableDeclaration(node);
+  }
+
+  var ids = t.getBindingIdentifiers(node);
+
+  extend(this.references, ids);
+
+  if (reference) return;
+
+  for (var key in ids) {
+    var id = ids[key];
+
+    this.checkBlockScopedCollisions(key, id);
+
+    this.registerType(key, id, node);
+    this.bindings[key] = id;
+  }
+
+  var kinds = this.declarationKinds[kind];
+  if (kinds) extend(kinds, ids);
+};
+
+Scope.prototype.registerVariableDeclaration = function (declar) {
+  var declars = declar.declarations;
+  for (var i = 0; i < declars.length; i++) {
+    this.register(declars[i], false, declar.kind);
+  }
+};
+
 var functionVariableVisitor = {
   enter: function (node, parent, scope, context, state) {
     if (t.isFor(node)) {
-      each(FOR_KEYS, function (key) {
+      each(t.FOR_INIT_KEYS, function (key) {
         var declar = node[key];
-        if (t.isVar(declar)) state.add(declar);
+        if (t.isVar(declar)) state.scope.register(declar);
       });
     }
 
@@ -158,64 +229,76 @@ var functionVariableVisitor = {
     // function identifier doesn't belong to this scope
     if (state.blockId && node === state.blockId) return;
 
+    // delegate block scope handling to the `blockVariableVisitor`
+    if (t.isBlockScoped(node)) return;
+
+    // this will be hit again once we traverse into it after this iteration
+    if (t.isExportDeclaration(node) && t.isDeclaration(node.declaration)) return;
+
     // we've ran into a declaration!
-    // we'll let the BlockStatement scope deal with `let` declarations unless
-    if (t.isDeclaration(node) && !t.isBlockScoped(node)) {
-      state.add(node);
-    }
+    if (t.isDeclaration(node)) state.scope.register(node);
   }
 };
 
 var programReferenceVisitor = {
-  enter: function (node, parent, scope, context, add) {
-    if (t.isReferencedIdentifier(node, parent) && !scope.has(node.name)) {
-      add(node, true);
+  enter: function (node, parent, scope, context, state) {
+    if (t.isReferencedIdentifier(node, parent) && !scope.hasReference(node.name)) {
+      state.register(node, true);
     }
   }
 };
 
 var blockVariableVisitor = {
-  enter: function (node, parent, scope, context, add) {
+  enter: function (node, parent, scope, context, state) {
     if (t.isBlockScoped(node)) {
-      add(node, false, t.isLet(node));
+      state.register(node);
     } else if (t.isScope(node)) {
       context.skip();
     }
   }
 };
 
-Scope.prototype.getInfo = function () {
+Scope.prototype.crawl = function () {
   var parent = this.parent;
   var block  = this.block;
-  var self   = this;
-  if (block._scopeInfo) return block._scopeInfo;
+  var i;
 
-  var info = block._scopeInfo = {};
-  var references = info.references = object();
-  var declarations = info.declarations = object();
-  var declarationKinds = info.declarationKinds = {};
+  //
 
-  var add = function (node, reference, throwOnDuplicate) {
-    self._add(node, references);
+  var info = block._scopeInfo;
+  if (info) {
+    extend(this, info);
+    return;
+  }
 
-    if (!reference) {
-      self._add(node, declarations, throwOnDuplicate);
-      self._add(node, declarationKinds[node.kind] = declarationKinds[node.kind] || object());
-    }
+  info = block._scopeInfo = {
+    declarationKinds: {
+      "const": object(),
+      "var":   object(),
+      "let":   object()
+    },
+
+    references: object(),
+    bindings:   object(),
+    types:      object(),
   };
 
-  if (parent && t.isBlockStatement(block) && t.isFor(parent.block, { body: block })) {
-    // delegate block let declarations to the parent loop
-    return info;
+  extend(this, info);
+
+  //
+
+  if (parent && t.isBlockStatement(block) && t.isLoop(parent.block, { body: block })) {
+    // delegate let bindings to the parent loop
+    return;
   }
 
   // ForStatement - left, init
 
-  if (t.isFor(block)) {
-    each(FOR_KEYS, function (key) {
-      var node = block[key];
-      if (t.isBlockScoped(node)) add(node, false, true);
-    });
+  if (t.isLoop(block)) {
+    for (i = 0; i < t.FOR_INIT_KEYS.length; i++) {
+      var node = block[t.FOR_INIT_KEYS[i]];
+      if (t.isBlockScoped(node)) this.register(node, false, true);
+    }
 
     if (t.isBlockStatement(block.body)) {
       block = block.body;
@@ -225,27 +308,35 @@ Scope.prototype.getInfo = function () {
   // Program, BlockStatement - let variables
 
   if (t.isBlockStatement(block) || t.isProgram(block)) {
-    traverse(block, blockVariableVisitor, this, add);
+    this.traverse(block, blockVariableVisitor, this);
   }
 
   // CatchClause - param
 
   if (t.isCatchClause(block)) {
-    add(block.param);
+    this.register(block.param);
   }
 
   // ComprehensionExpression - blocks
 
   if (t.isComprehensionExpression(block)) {
-    add(block);
+    this.register(block);
+  }
+
+  // Function - params, rest
+
+  if (t.isFunction(block)) {
+    for (i = 0; i < block.params.length; i++) {
+      this.register(block.params[i]);
+    }
   }
 
   // Program, Function - var variables
 
   if (t.isProgram(block) || t.isFunction(block)) {
-    traverse(block, functionVariableVisitor, this, {
+    this.traverse(block, functionVariableVisitor, {
       blockId: block.id,
-      add:     add
+      scope:   this
     });
   }
 
@@ -253,25 +344,15 @@ Scope.prototype.getInfo = function () {
     if (!t.isProperty(this.parentBlock, { method: true })) {
       // SpiderMonkey AST doesn't use MethodDefinition here when it probably
       // should since they should be semantically the same?
-      add(block.id);
+      this.register(block.id);
     }
   }
 
   // Program
 
   if (t.isProgram(block)) {
-    traverse(block, programReferenceVisitor, this, add);
+    this.traverse(block, programReferenceVisitor, this);
   }
-
-  // Function - params, rest
-
-  if (t.isFunction(block)) {
-    each(block.params, function (param) {
-      add(param);
-    });
-  }
-
-  return info;
 };
 
 /**
@@ -304,12 +385,20 @@ Scope.prototype.push = function (opts) {
  * Walk up the scope tree until we hit a `Function` and then
  * push our `node` to it's references.
  *
+ * @param {String} kind
  * @param {Object} node
  */
 
-Scope.prototype.add = function (node) {
+Scope.prototype.addDeclarationToFunctionScope = function (kind, node) {
   var scope = this.getFunctionParent();
-  scope._add(node, scope.references);
+  var ids   = t.getBindingIdentifiers(node);
+
+  extend(scope.bindings, ids);
+  extend(scope.references, ids);
+
+  // this ignores the duplicate declaration logic specified in `getInfo`
+  // but it doesn't really matter
+  extend(scope.declarationKinds[kind], ids);
 };
 
 /**
@@ -326,17 +415,17 @@ Scope.prototype.getFunctionParent = function () {
 };
 
 /**
- * Walks the scope tree and gathers **all** declarations.
+ * Walks the scope tree and gathers **all** bindings.
  *
  * @returns {Object}
  */
 
-Scope.prototype.getAllDeclarations = function () {
+Scope.prototype.getAllBindings = function () {
   var ids = object();
 
   var scope = this;
   do {
-    defaults(ids, scope.declarations);
+    defaults(ids, scope.bindings);
     scope = scope.parent;
   } while (scope);
 
@@ -362,77 +451,56 @@ Scope.prototype.getAllDeclarationsOfKind = function (kind) {
   return ids;
 };
 
-/**
- * Description
- *
- * @param {String} [id]
- * @param {Boolean} [decl]
- */
+//
 
-Scope.prototype.get = function (id, decl) {
-  return id && (this.getOwn(id, decl) || this.parentGet(id, decl));
+Scope.prototype.get = function (id, type) {
+  return id && (this.getOwn(id, type) || this.parentGet(id, type));
 };
 
-/**
- * Description
- *
- * @param {String} [id]
- * @param {Boolean} [decl]
- */
-
-Scope.prototype.getOwn = function (id, decl) {
-  var refs = this.references;
-  if (decl) refs = this.declarations;
-  return has(refs, id) && refs[id];
+Scope.prototype.getOwn = function (id, type) {
+  var refs = {
+    reference: this.references,
+    binding:   this.bindings,
+    type:      this.types
+  }[type];
+  return refs && has(refs, id) && refs[id];
 };
 
-/**
- * Description
- *
- * @param {String} [id]
- * @param {Boolean} [decl]
- */
-
-Scope.prototype.parentGet = function (id, decl) {
-  return this.parent && this.parent.get(id, decl);
+Scope.prototype.parentGet = function (id, type) {
+  return this.parent && this.parent.get(id, type);
 };
 
-/**
- * Description
- *
- * @param {String} [id]
- * @param {Boolean} [decl]
- * @returns {Boolean}
- */
-
-Scope.prototype.has = function (id, decl) {
+Scope.prototype.has = function (id, type) {
   if (!id) return false;
-  if (this.hasOwn(id, decl)) return true;
-  if (this.parentHas(id, decl)) return true;
+  if (this.hasOwn(id, type)) return true;
+  if (this.parentHas(id, type)) return true;
   if (contains(Scope.defaultDeclarations, id)) return true;
   return false;
 };
 
-/**
- * Description
- *
- * @param {String} [id]
- * @param {Boolean} [decl]
- * @returns {Boolean}
- */
-
-Scope.prototype.hasOwn = function (id, decl) {
-  return !!this.getOwn(id, decl);
+Scope.prototype.hasOwn = function (id, type) {
+  return !!this.getOwn(id, type);
 };
 
-/**
- * Description
- *
- * @param {String} [id]
- * @param {Boolean} [decl]
- * @returns {Boolean}
- */
-
-Scope.prototype.parentHas = function (id, decl) {
-  return this.parent && this.parent.has(id, decl);
+Scope.prototype.parentHas = function (id, type) {
+  return this.parent && this.parent.has(id, type);
 };
+
+each({
+  reference: "Reference",
+  binding: "Binding",
+  type: "Type"
+}, function (title, type) {
+  each([
+    "get",
+    "has",
+    "getOwn",
+    "hasOwn",
+    "parentGet",
+    "parentHas",
+  ], function (methodName) {
+    Scope.prototype[methodName + title] = function (id) {
+      return this[methodName](id, type);
+    };
+  });
+});

lib/6to5/types/alias-keys.json

@@ -3,13 +3,13 @@
   "BreakStatement":      ["Statement"],
   "ContinueStatement":   ["Statement"],
   "DebuggerStatement":   ["Statement"],
-  "DoWhileStatement":    ["Statement", "Loop", "While"],
+  "DoWhileStatement":    ["Statement", "Loop", "While", "Scope"],
   "IfStatement":         ["Statement"],
   "ReturnStatement":     ["Statement"],
   "SwitchStatement":     ["Statement"],
   "ThrowStatement":      ["Statement"],
   "TryStatement":        ["Statement"],
-  "WhileStatement":      ["Statement", "Loop", "While"],
+  "WhileStatement":      ["Statement", "Loop", "While", "Scope"],
   "WithStatement":       ["Statement"],
   "EmptyStatement":      ["Statement"],
   "LabeledStatement":    ["Statement"],
@@ -44,28 +44,39 @@
   "ArrayPattern":      ["Pattern"],
   "AssignmentPattern": ["Pattern"],
 
-  "Property": ["UserWhitespacable"],
+  "Property":   ["UserWhitespacable"],
   "JSXElement": ["UserWhitespacable", "Expression"],
 
-  "ArrayExpression": ["Expression"],
-  "AssignmentExpression": ["Expression"],
-  "AwaitExpression": ["Expression"],
-  "BindFunctionExpression": ["Expression"],
-  "BindMemberExpression": ["Expression"],
-  "CallExpression": ["Expression"],
-  "ComprehensionExpression": ["Expression", "Scope"],
-  "ConditionalExpression": ["Expression"],
-  "Identifier": ["Expression"],
-  "Literal": ["Expression"],
-  "MemberExpression": ["Expression"],
-  "NewExpression": ["Expression"],
-  "ObjectExpression": ["Expression"],
-  "SequenceExpression": ["Expression"],
-  "TaggedTemplateExpression": ["Expression"],
-  "ThisExpression": ["Expression"],
-  "UpdateExpression": ["Expression"],
+  "ArrayExpression":           ["Expression"],
+  "AssignmentExpression":      ["Expression"],
+  "AwaitExpression":           ["Expression"],
+  "BindFunctionExpression":    ["Expression"],
+  "BindMemberExpression":      ["Expression"],
+  "CallExpression":            ["Expression"],
+  "ComprehensionExpression":   ["Expression", "Scope"],
+  "ConditionalExpression":     ["Expression"],
+  "Identifier":                ["Expression"],
+  "Literal":                   ["Expression"],
+  "MemberExpression":          ["Expression"],
+  "NewExpression":             ["Expression"],
+  "ObjectExpression":          ["Expression"],
+  "SequenceExpression":        ["Expression"],
+  "TaggedTemplateExpression":  ["Expression"],
+  "ThisExpression":            ["Expression"],
+  "UpdateExpression":          ["Expression"],
   "VirtualPropertyExpression": ["Expression"],
-  "JSXEmptyExpression": ["Expression"],
-  "JSXMemberExpression": ["Expression"],
-  "YieldExpression": ["Expression"]
+  "JSXEmptyExpression":        ["Expression"],
+  "JSXMemberExpression":       ["Expression"],
+  "YieldExpression":           ["Expression"],
+
+  "JSXAttribute":           ["JSX"],
+  "JSXClosingElement":      ["JSX"],
+  "JSXElement":             ["JSX"],
+  "JSXEmptyExpression":     ["JSX"],
+  "JSXExpressionContainer": ["JSX"],
+  "JSXIdentifier":          ["JSX"],
+  "JSXMemberExpression":    ["JSX"],
+  "JSXNamespacedName":      ["JSX"],
+  "JSXOpeningElement":      ["JSX"],
+  "JSXSpreadAttribute":     ["JSX"]
 }

lib/6to5/types/index.js

@@ -34,11 +34,11 @@ function registerType(type, skipAliasCheck) {
 }
 
 t.STATEMENT_OR_BLOCK_KEYS = ["consequent", "body"];
-t.NATIVE_TYPE_NAMES = ["Array", "Object", "Number", "Boolean", "Date", "Array", "String"];
+t.NATIVE_TYPE_NAMES       = ["Array", "Object", "Number", "Boolean", "Date", "Array", "String"];
+t.FOR_INIT_KEYS           = ["left", "init"];
 
 t.VISITOR_KEYS = require("./visitor-keys");
-
-t.ALIAS_KEYS = require("./alias-keys");
+t.ALIAS_KEYS   = require("./alias-keys");
 
 t.FLIPPED_ALIAS_KEYS = {};
 
@@ -127,9 +127,7 @@ t.toComputedKey = function (node, key) {
 };
 
 /*
- * Shallowly checks to see if the passed `node` will evaluate to a
- * falsy. This is if `node` is a `Literal` and `value` is falsy or
- * `node` is an `Identifier` with a name of `undefiend`.
+ * Shallowly checks to see if the passed `node` is falsy.
  *
  * @param {Object} node
  * @returns {Boolean}
@@ -560,17 +558,14 @@ t.toBlock = function (node, parent) {
 };
 
 /**
- * Return a list of identifiers that will be assigned
- * as a result of runtime evaluation.
- *
- * If an identifier is passed as `node` instead of a
- * declaration then it's assumed to be an assignable.
+ * Return a list of binding identifiers associated with
+ * the input `node`.
  *
  * @param {Object} node
  * @returns {Array|Object}
  */
 
-t.getDeclarations = function (node) {
+t.getBindingIdentifiers = function (node) {
   var search = [].concat(node);
   var ids    = object();
 
@@ -578,7 +573,7 @@ t.getDeclarations = function (node) {
     var id = search.shift();
     if (!id) continue;
 
-    var keys = t.getDeclarations.keys[id.type];
+    var keys = t.getBindingIdentifiers.keys[id.type];
 
     if (t.isIdentifier(id)) {
       ids[id.name] = id;
@@ -597,7 +592,7 @@ t.getDeclarations = function (node) {
   return ids;
 };
 
-t.getDeclarations.keys = {
+t.getBindingIdentifiers.keys = {
   AssignmentExpression: ["left"],
   ImportBatchSpecifier: ["name"],
   ImportSpecifier: ["name", "id"],
@@ -608,6 +603,7 @@ t.getDeclarations.keys = {
   MemeberExpression: ["object"],
   SpreadElement: ["argument"],
   RestElement: ["argument"],
+  UpdateExpression: ["argument"],
   Property: ["value"],
   ComprehensionBlock: ["left"],
   AssignmentPattern: ["left"],
@@ -638,7 +634,7 @@ t.isLet = function (node) {
  */
 
 t.isBlockScoped = function (node) {
-  return t.isFunctionDeclaration(node) || t.isLet(node);
+  return t.isFunctionDeclaration(node) || t.isClassDeclaration(node) || t.isLet(node);
 };
 
 /**

lib/6to5/util.js

@@ -16,7 +16,6 @@ var isNumber   = require("lodash/lang/isNumber");
 var isString   = require("lodash/lang/isString");
 var isRegExp   = require("lodash/lang/isRegExp");
 var isEmpty    = require("lodash/lang/isEmpty");
-var clone      = require("lodash/lang/clone");
 var cloneDeep  = require("lodash/lang/cloneDeep");
 var has        = require("lodash/object/has");
 var contains   = require("lodash/collection/contains");
@@ -81,73 +80,6 @@ exports.sourceMapToComment = function (map) {
   return "//# sourceMappingURL=data:application/json;base64," + base64;
 };
 
-exports.pushMutatorMap = function (mutatorMap, key, kind, computed, value) {
-  var alias;
-
-  if (t.isIdentifier(key)) {
-    alias = key.name;
-    if (computed) alias = "computed:" + alias;
-  } else if (t.isLiteral(key)) {
-    alias = String(key.value);
-  } else {
-    alias = JSON.stringify(traverse.removeProperties(cloneDeep(key)));
-  }
-
-  var map;
-  if (has(mutatorMap, alias)) {
-    map = mutatorMap[alias];
-  } else {
-    map = {};
-  }
-  mutatorMap[alias] = map;
-
-  map._key = key;
-  if (computed) {
-    map._computed = true;
-  }
-
-  map[kind] = value;
-};
-
-exports.buildDefineProperties = function (mutatorMap) {
-  var objExpr = t.objectExpression([]);
-
-  each(mutatorMap, function (map) {
-    var mapNode = t.objectExpression([]);
-
-    var propNode = t.property("init", map._key, mapNode, map._computed);
-
-    if (!map.get && !map.set) {
-      map.writable = t.literal(true);
-    }
-
-    if (map.enumerable === false) {
-      delete map.enumerable;
-    } else {
-      map.enumerable = t.literal(true);
-    }
-
-    map.configurable = t.literal(true);
-
-    each(map, function (node, key) {
-      if (key[0] === "_") return;
-
-      node = clone(node);
-      var inheritNode = node;
-      if (t.isMethodDefinition(node)) node = node.value;
-
-      var prop = t.property("init", t.identifier(key), node);
-      t.inheritsComments(prop, inheritNode);
-      t.removeComments(inheritNode);
-      mapNode.properties.push(prop);
-    });
-
-    objExpr.properties.push(propNode);
-  });
-
-  return objExpr;
-};
-
 var templateVisitor = {
   enter: function (node, parent, scope, context, nodes) {
     if (t.isIdentifier(node) && has(nodes, node.name)) {
@@ -191,7 +123,7 @@ exports.repeat = function (width, cha) {
   return result;
 };
 
-exports.normaliseAst = function (ast, comments, tokens) {
+exports.normalizeAst = function (ast, comments, tokens) {
   if (ast && ast.type === "Program") {
     return t.file(ast, comments || [], tokens || []);
   } else {
@@ -206,7 +138,7 @@ exports.parse = function (opts, code, callback) {
 
     var ast = acorn.parse(code, {
       allowImportExportEverywhere: opts.allowImportExportEverywhere,
-      allowReturnOutsideFunction:  true,
+      allowReturnOutsideFunction:  !opts._anal,
       ecmaVersion:                 opts.experimental ? 7 : 6,
       playground:                  opts.playground,
       strictMode:                  opts.strictMode,
@@ -218,7 +150,7 @@ exports.parse = function (opts, code, callback) {
 
     estraverse.attachComments(ast, comments, tokens);
 
-    ast = exports.normaliseAst(ast, comments, tokens);
+    ast = exports.normalizeAst(ast, comments, tokens);
 
     if (callback) {
       return callback(ast);

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "3.3.4",
+  "version": "3.3.12",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://6to5.org/",
   "repository": "6to5/6to5",
@@ -9,6 +9,7 @@
   "main": "lib/6to5/index.js",
   "bin": {
     "6to5": "./bin/6to5/index.js",
+    "6to5-minify": "./bin/6to5-minify",
     "6to5-node": "./bin/6to5-node",
     "6to5-runtime": "./bin/6to5-runtime"
   },

packages/6to5-runtime/package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5-runtime",
   "description": "6to5 selfContained runtime",
-  "version": "3.3.3",
+  "version": "3.3.11",
   "repository": "6to5/6to5",
   "author": "Sebastian McKenzie <sebmck@gmail.com>"
 }

test/_helper.js

@@ -1,9 +1,10 @@
-var util = require("../lib/6to5/util");
-var path = require("path");
-var fs   = require("fs");
-var _    = require("lodash");
+var esvalid = require("esvalid");
+var util    = require("../lib/6to5/util");
+var path    = require("path");
+var fs      = require("fs");
+var _       = require("lodash");
 
-var humanise = function (val, noext) {
+var humanize = function (val, noext) {
   if (noext) val = path.basename(val, path.extname(val));
   return val.replace(/-/g, " ");
 };
@@ -18,6 +19,17 @@ var readFile = exports.readFile = function (filename) {
   }
 };
 
+exports.esvalid = function (ast, loc) {
+  var errors = esvalid.errors(ast);
+  if (errors.length) {
+    var msg = [];
+    _.each(errors, function (err) {
+      msg.push(err.message + " - " + JSON.stringify(err.node));
+    });
+    throw new Error(loc + ": " + msg.join(". "));
+  }
+};
+
 exports.assertVendor = function (name) {
   if (!fs.existsSync(__dirname + "/../vendor/" + name)) {
     console.error("No vendor/" + name + " - run `make bootstrap`");
@@ -37,7 +49,7 @@ exports.get = function (entryName, entryLoc) {
     var suite = {
       options: {},
       tests: [],
-      title: humanise(suiteName),
+      title: humanize(suiteName),
       filename: entryLoc + "/" + suiteName
     };
     suites.push(suite);
@@ -83,7 +95,7 @@ exports.get = function (entryName, entryLoc) {
       if (taskOptsLoc) _.merge(taskOpts, require(taskOptsLoc));
 
       var test = {
-        title: humanise(taskName, true),
+        title: humanize(taskName, true),
         disabled: taskName[0] === ".",
         options: taskOpts,
         exec: {

test/_transformation-helper.js

@@ -2,7 +2,6 @@ var genHelpers = require("./_generator-helpers");
 var transform  = require("../lib/6to5/transformation");
 var sourceMap  = require("source-map");
 var codeFrame  = require("../lib/6to5/helpers/code-frame");
-var esvalid    = require("esvalid");
 var Module     = require("module");
 var helper     = require("./_helper");
 var assert     = require("assert");
@@ -55,15 +54,7 @@ var run = function (task, done) {
 
   var checkAst = function (result, opts) {
     if (noCheckAst) return;
-
-    var errors = esvalid.errors(result.ast.program);
-    if (errors.length) {
-      var msg = [];
-      _.each(errors, function (err) {
-        msg.push(err.message + " - " + JSON.stringify(err.node));
-      });
-      throw new Error(opts.loc + ": " + msg.join(". "));
-    }
+    helper.esvalid(result.ast.program, opts.loc);
   };
 
   if (execCode) {
@@ -114,10 +105,10 @@ var run = function (task, done) {
     var consumer = new sourceMap.SourceMapConsumer(result.map);
 
     _.each(task.sourceMappings, function (mapping, i) {
-      var expect = mapping.original;
+      var actual = mapping.original;
 
-      var actual = consumer.originalPositionFor(mapping.generated);
-      chai.expect({ line: actual.line, column: actual.column }).to.deep.equal(expect);
+      var expect = consumer.originalPositionFor(mapping.generated);
+      chai.expect({ line: expect.line, column: expect.column }).to.deep.equal(actual);
     });
   }
 };

test/fixtures/bin/6to5/dir --out-dir --source-maps-inline/out-files/lib/bar/bar.js

@@ -1,4 +1,8 @@
 "use strict";
 
-var Test = function Test() {};
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9iYXIvYmFyLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7O0lBQU0sZ0JBQUEiLCJmaWxlIjoic3JjL2Jhci9iYXIuanMiLCJzb3VyY2VzQ29udGVudCI6WyJjbGFzcyBUZXN0IHtcblxufSJdfQ==
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
+var Test = function Test() {
+  _classCallCheck(this, Test);
+};
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9iYXIvYmFyLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7Ozs7SUFBTSxJQUFJLFlBQUosSUFBSTt3QkFBSixJQUFJIiwiZmlsZSI6InNyYy9iYXIvYmFyLmpzIiwic291cmNlc0NvbnRlbnQiOlsiY2xhc3MgVGVzdCB7XG5cbn0iXX0=

test/fixtures/bin/6to5/dir --out-dir --source-maps-inline/out-files/lib/foo.js

@@ -3,4 +3,4 @@
 arr.map(function (x) {
   return x * MULTIPLIER;
 });
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9mb28uanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7QUFBQSxJQUFJLElBQUksVUFBQTtTQUFLLElBQUkiLCJmaWxlIjoic3JjL2Zvby5qcyIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogTVVMVElQTElFUik7Il19
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9mb28uanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7QUFBQSxHQUFHLENBQUMsR0FBRyxDQUFDLFVBQUEsQ0FBQztTQUFJLENBQUMsR0FBRyxVQUFVO0NBQUEsQ0FBQyxDQUFDIiwiZmlsZSI6InNyYy9mb28uanMiLCJzb3VyY2VzQ29udGVudCI6WyJhcnIubWFwKHggPT4geCAqIE1VTFRJUExJRVIpOyJdfQ==

test/fixtures/bin/6to5/dir --out-dir --source-maps/out-files/lib/bar/bar.js

@@ -1,4 +1,8 @@
 "use strict";
 
-var Test = function Test() {};
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
+var Test = function Test() {
+  _classCallCheck(this, Test);
+};
 //# sourceMappingURL=bar.js.map

test/fixtures/bin/6to5/dir --out-dir --source-maps/out-files/lib/bar/bar.js.map

@@ -1 +1 @@
-{"version":3,"sources":["src/bar/bar.js"],"names":[],"mappings":";;IAAM,gBAAA","file":"src/bar/bar.js","sourcesContent":["class Test {\n\n}"]}
+{"version":3,"sources":["src/bar/bar.js"],"names":[],"mappings":";;;;IAAM,IAAI,YAAJ,IAAI;wBAAJ,IAAI","file":"src/bar/bar.js","sourcesContent":["class Test {\n\n}"]}

test/fixtures/bin/6to5/dir --out-dir --source-maps/out-files/lib/foo.js.map

@@ -1 +1 @@
-{"version":3,"sources":["src/foo.js"],"names":[],"mappings":";;AAAA,IAAI,IAAI,UAAA;SAAK,IAAI","file":"src/foo.js","sourcesContent":["arr.map(x => x * MULTIPLIER);"]}
+{"version":3,"sources":["src/foo.js"],"names":[],"mappings":";;AAAA,GAAG,CAAC,GAAG,CAAC,UAAA,CAAC;SAAI,CAAC,GAAG,UAAU;CAAA,CAAC,CAAC","file":"src/foo.js","sourcesContent":["arr.map(x => x * MULTIPLIER);"]}

test/fixtures/bin/6to5/dir --out-dir/out-files/lib/bar/bar.js

@@ -1,3 +1,7 @@
 "use strict";
 
-var Test = function Test() {};
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
+var Test = function Test() {
+  _classCallCheck(this, Test);
+};

test/fixtures/bin/6to5/filename --out-file --source-maps-inline/out-files/script2.js

@@ -4,4 +4,4 @@ arr.map(function (x) {
   return x * MULTIPLIER;
 });
 
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiOztBQUFBLElBQUksSUFBSSxVQUFBO1NBQUssSUFBSSIsImZpbGUiOiJzY3JpcHQyLmpzIiwic291cmNlc0NvbnRlbnQiOlsiYXJyLm1hcCh4ID0+IHggKiBNVUxUSVBMSUVSKTsiXX0=
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiOztBQUFBLEdBQUcsQ0FBQyxHQUFHLENBQUMsVUFBQSxDQUFDO1NBQUksQ0FBQyxHQUFHLFVBQVU7Q0FBQSxDQUFDLENBQUMiLCJmaWxlIjoic2NyaXB0Mi5qcyIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogTVVMVElQTElFUik7Il19

test/fixtures/bin/6to5/filenames --out-file --source-maps-inline/out-files/script3.js

@@ -1,10 +1,14 @@
 "use strict";
 
-var Test = function Test() {};
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
+var Test = function Test() {
+  _classCallCheck(this, Test);
+};
 "use strict";
 
 arr.map(function (x) {
   return x * MULTIPLIER;
 });
 
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyIsInNjcmlwdDIuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7SUFBTSxnQkFBQTs7OztBQ0FOLElBQUksSUFBSSxVQUFBO1NBQUssSUFBSSIsImZpbGUiOiJzY3JpcHQzLmpzIiwic291cmNlc0NvbnRlbnQiOlsiY2xhc3MgVGVzdCB7XG5cbn0iLCJhcnIubWFwKHggPT4geCAqIE1VTFRJUExJRVIpOyJdfQ==
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyIsInNjcmlwdDIuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7OztJQUFNLElBQUksWUFBSixJQUFJO3dCQUFKLElBQUk7Ozs7O0FDQVYsR0FBRyxDQUFDLEdBQUcsQ0FBQyxVQUFBLENBQUM7U0FBSSxDQUFDLEdBQUcsVUFBVTtDQUFBLENBQUMsQ0FBQyIsImZpbGUiOiJzY3JpcHQzLmpzIiwic291cmNlc0NvbnRlbnQiOlsiY2xhc3MgVGVzdCB7XG5cbn0iLCJhcnIubWFwKHggPT4geCAqIE1VTFRJUExJRVIpOyJdfQ==

test/fixtures/bin/6to5/filenames --out-file --source-maps/out-files/script3.js

@@ -1,6 +1,10 @@
 "use strict";
 
-var Test = function Test() {};
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
+var Test = function Test() {
+  _classCallCheck(this, Test);
+};
 "use strict";
 
 arr.map(function (x) {

test/fixtures/bin/6to5/filenames --out-file --source-maps/out-files/script3.js.map

@@ -1 +1 @@
-{"version":3,"sources":["script.js","script2.js"],"names":[],"mappings":";;IAAM,gBAAA;;;;ACAN,IAAI,IAAI,UAAA;SAAK,IAAI","file":"script3.js","sourcesContent":["class Test {\n\n}","arr.map(x => x * MULTIPLIER);"]}
+{"version":3,"sources":["script.js","script2.js"],"names":[],"mappings":";;;;IAAM,IAAI,YAAJ,IAAI;wBAAJ,IAAI;;;;;ACAV,GAAG,CAAC,GAAG,CAAC,UAAA,CAAC;SAAI,CAAC,GAAG,UAAU;CAAA,CAAC,CAAC","file":"script3.js","sourcesContent":["class Test {\n\n}","arr.map(x => x * MULTIPLIER);"]}

test/fixtures/bin/6to5/filenames --out-file/out-files/script3.js

@@ -1,6 +1,10 @@
 "use strict";
 
-var Test = function Test() {};
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
+var Test = function Test() {
+  _classCallCheck(this, Test);
+};
 "use strict";
 
 arr.map(function (x) {

test/fixtures/bin/6to5/stdin --out-file --source-maps/out-files/test.js.map

@@ -1 +1 @@
-{"version":3,"sources":["stdin"],"names":[],"mappings":";;AAAA,IAAI,IAAI,UAAA;SAAK,IAAI","file":"test.js","sourcesContent":["arr.map(x => x * x);"]}
+{"version":3,"sources":["stdin"],"names":[],"mappings":";;AAAA,GAAG,CAAC,GAAG,CAAC,UAAA,CAAC;SAAI,CAAC,GAAG,CAAC;CAAA,CAAC,CAAC","file":"test.js","sourcesContent":["arr.map(x => x * x);"]}

test/fixtures/bin/6to5/stdin --source-maps-inline/stdout.txt

@@ -4,4 +4,4 @@ arr.map(function (x) {
   return x * x;
 });
 
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7O0FBQUEsSUFBSSxJQUFJLFVBQUE7U0FBSyxJQUFJIiwiZmlsZSI6InN0ZG91dCIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogeCk7Il19
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7O0FBQUEsR0FBRyxDQUFDLEdBQUcsQ0FBQyxVQUFBLENBQUM7U0FBSSxDQUFDLEdBQUcsQ0FBQztDQUFBLENBQUMsQ0FBQyIsImZpbGUiOiJzdGRvdXQiLCJzb3VyY2VzQ29udGVudCI6WyJhcnIubWFwKHggPT4geCAqIHgpOyJdfQ==

test/fixtures/esnext/es6-classes/super-change-proto.js

@@ -1,21 +0,0 @@
-var log = '';
-
-class Base {
-  p() { log += '[Base]'; }
-}
-
-class OtherBase {
-  p() { log += '[OtherBase]'; }
-}
-
-class Derived extends Base {
-  p() {
-    log += '[Derived]';
-    super.p();
-    Derived.prototype.__proto__ = OtherBase.prototype;
-    super.p();
-  }
-}
-
-new Derived().p();
-assert.equal(log, '[Derived][Base][OtherBase]');

test/fixtures/transformation/api/blacklist/expected.js

@@ -1,5 +1,9 @@
 "use strict";
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = function Test() {
+  _classCallCheck(this, Test);
+
   arr.map(x => x * x);
-};
+};

test/fixtures/transformation/async-to-generator/async/expected.js

@@ -4,8 +4,12 @@ var _asyncToGenerator = function (fn) { return function () { var gen = fn.apply(
 
 var _prototypeProperties = function (child, staticProps, instanceProps) { if (staticProps) Object.defineProperties(child, staticProps); if (instanceProps) Object.defineProperties(child.prototype, instanceProps); };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Foo = (function () {
-  function Foo() {}
+  function Foo() {
+    _classCallCheck(this, Foo);
+  }
 
   _prototypeProperties(Foo, null, {
     foo: {

test/fixtures/transformation/bluebird-coroutines/class/expected.js

@@ -4,8 +4,12 @@ var _bluebird = require("bluebird");
 
 var _prototypeProperties = function (child, staticProps, instanceProps) { if (staticProps) Object.defineProperties(child, staticProps); if (instanceProps) Object.defineProperties(child.prototype, instanceProps); };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Foo = (function () {
-  function Foo() {}
+  function Foo() {
+    _classCallCheck(this, Foo);
+  }
 
   _prototypeProperties(Foo, null, {
     foo: {

test/fixtures/transformation/es6-classes-loose/accessing-super-class/expected.js

@@ -3,9 +3,13 @@
 var _slice = Array.prototype.slice;
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function (Foo) {
   function Test() {
     var _Foo$prototype$test, _Foo$prototype$test2;
+    _classCallCheck(this, Test);
+
     woops["super"].test();
     Foo.call(this);
     Foo.prototype.test.call(this);

test/fixtures/transformation/es6-classes-loose/accessing-super-properties/expected.js

@@ -2,8 +2,12 @@
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function (Foo) {
   function Test() {
+    _classCallCheck(this, Test);
+
     Foo.prototype.test;
     Foo.prototype.test.whatever;
   }

test/fixtures/transformation/es6-classes-loose/calling-super-properties/expected.js

@@ -2,8 +2,12 @@
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function (Foo) {
   function Test() {
+    _classCallCheck(this, Test);
+
     Foo.prototype.test.whatever();
     Foo.prototype.test.call(this);
   }

test/fixtures/transformation/es6-classes-loose/super-class-id-member-expression/expected.js

@@ -2,8 +2,12 @@
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var BaseController = (function (_Chaplin$Controller) {
   function BaseController() {
+    _classCallCheck(this, BaseController);
+
     if (_Chaplin$Controller != null) {
       _Chaplin$Controller.apply(this, arguments);
     }
@@ -16,6 +20,8 @@ var BaseController = (function (_Chaplin$Controller) {
 
 var BaseController2 = (function (_Chaplin$Controller$Another) {
   function BaseController2() {
+    _classCallCheck(this, BaseController2);
+
     if (_Chaplin$Controller$Another != null) {
       _Chaplin$Controller$Another.apply(this, arguments);
     }

test/fixtures/transformation/es6-classes-loose/super-class/expected.js

@@ -2,8 +2,12 @@
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function (Foo) {
   function Test() {
+    _classCallCheck(this, Test);
+
     if (Foo != null) {
       Foo.apply(this, arguments);
     }

test/fixtures/transformation/es6-classes-loose/super-function-fallback/expected.js

@@ -1,5 +1,9 @@
 "use strict";
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = function Test() {
+  _classCallCheck(this, Test);
+
   Function.prototype.hasOwnProperty.call(this, "test");
-};
+};

test/fixtures/transformation/es6-classes/accessing-super-class/expected.js

@@ -7,18 +7,22 @@ var _get = function get(object, property, receiver) { var desc = Object.getOwnPr
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function (Foo) {
   function Test() {
     var _get2, _get3;
+    _classCallCheck(this, Test);
+
     woops["super"].test();
-    _get(Object.getPrototypeOf(Test.prototype), "constructor", this).call(this);
-    _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
+    _get(Foo.prototype, "constructor", this).call(this);
+    _get(Foo.prototype, "test", this).call(this);
 
-    _get(Object.getPrototypeOf(Test.prototype), "constructor", this).apply(this, arguments);
-    (_get2 = _get(Object.getPrototypeOf(Test.prototype), "constructor", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
+    _get(Foo.prototype, "constructor", this).apply(this, arguments);
+    (_get2 = _get(Foo.prototype, "constructor", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
 
-    _get(Object.getPrototypeOf(Test.prototype), "test", this).apply(this, arguments);
-    (_get3 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get3, [this, "test"].concat(_slice.call(arguments)));
+    _get(Foo.prototype, "test", this).apply(this, arguments);
+    (_get3 = _get(Foo.prototype, "test", this)).call.apply(_get3, [this, "test"].concat(_slice.call(arguments)));
   }
 
   _inherits(Test, Foo);
@@ -27,9 +31,9 @@ var Test = (function (Foo) {
     foo: {
       value: function foo() {
         var _get2;
-        _get(Object.getPrototypeOf(Test), "foo", this).call(this);
-        _get(Object.getPrototypeOf(Test), "foo", this).apply(this, arguments);
-        (_get2 = _get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
+        _get(Foo, "foo", this).call(this);
+        _get(Foo, "foo", this).apply(this, arguments);
+        (_get2 = _get(Foo, "foo", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
       },
       writable: true,
       configurable: true
@@ -38,9 +42,9 @@ var Test = (function (Foo) {
     test: {
       value: function test() {
         var _get2;
-        _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
-        _get(Object.getPrototypeOf(Test.prototype), "test", this).apply(this, arguments);
-        (_get2 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
+        _get(Foo.prototype, "test", this).call(this);
+        _get(Foo.prototype, "test", this).apply(this, arguments);
+        (_get2 = _get(Foo.prototype, "test", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
       },
       writable: true,
       configurable: true

test/fixtures/transformation/es6-classes/accessing-super-properties/expected.js

@@ -4,10 +4,14 @@ var _get = function get(object, property, receiver) { var desc = Object.getOwnPr
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function (Foo) {
   function Test() {
-    _get(Object.getPrototypeOf(Test.prototype), "test", this);
-    _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever;
+    _classCallCheck(this, Test);
+
+    _get(Foo.prototype, "test", this);
+    _get(Foo.prototype, "test", this).whatever;
   }
 
   _inherits(Test, Foo);

test/fixtures/transformation/es6-classes/calling-super-properties/expected.js

@@ -6,10 +6,14 @@ var _get = function get(object, property, receiver) { var desc = Object.getOwnPr
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function (Foo) {
   function Test() {
-    _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever();
-    _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
+    _classCallCheck(this, Test);
+
+    _get(Foo.prototype, "test", this).whatever();
+    _get(Foo.prototype, "test", this).call(this);
   }
 
   _inherits(Test, Foo);
@@ -17,7 +21,7 @@ var Test = (function (Foo) {
   _prototypeProperties(Test, {
     test: {
       value: function test() {
-        return _get(Object.getPrototypeOf(Test), "wow", this).call(this);
+        return _get(Foo, "wow", this).call(this);
       },
       writable: true,
       configurable: true

test/fixtures/transformation/es6-classes/constructor/expected.js

@@ -2,12 +2,18 @@
 
 var _inherits = function (subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) subClass.__proto__ = superClass; };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = function Test() {
+  _classCallCheck(this, Test);
+
   this.state = "test";
 };
 
 var Foo = (function (Bar) {
   function Foo() {
+    _classCallCheck(this, Foo);
+
     this.state = "test";
   }
 

test/fixtures/transformation/es6-classes/instance-getter-and-setter/expected.js

@@ -2,8 +2,12 @@
 
 var _prototypeProperties = function (child, staticProps, instanceProps) { if (staticProps) Object.defineProperties(child, staticProps); if (instanceProps) Object.defineProperties(child.prototype, instanceProps); };
 
+var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
+
 var Test = (function () {
-  function Test() {}
+  function Test() {
+    _classCallCheck(this, Test);
+  }
 
   _prototypeProperties(Test, null, {
     test: {