@babel/eslint-parser: refactor configuration logic (#10860)

eslint/babel-eslint-parser/src/configuration.js

@@ -0,0 +1,61 @@
+import { loadPartialConfig } from "@babel/core";
+
+export function normalizeESLintConfig(options) {
+  const defaultOptions = {
+    babelOptions: {},
+    ecmaVersion: 2020,
+    sourceType: "module",
+    allowImportExportEverywhere: false,
+  };
+
+  return Object.assign(defaultOptions, options);
+}
+
+export function normalizeBabelParseConfig(options) {
+  const parseOptions = {
+    sourceType: options.sourceType,
+    filename: options.filePath,
+    cwd: options.babelOptions.cwd,
+    root: options.babelOptions.root,
+    rootMode: options.babelOptions.rootMode,
+    envName: options.babelOptions.envName,
+    configFile: options.babelOptions.configFile,
+    babelrc: options.babelOptions.babelrc,
+    babelrcRoots: options.babelOptions.babelrcRoots,
+    extends: options.babelOptions.extends,
+    env: options.babelOptions.env,
+    overrides: options.babelOptions.overrides,
+    test: options.babelOptions.test,
+    include: options.babelOptions.include,
+    exclude: options.babelOptions.exclude,
+    ignore: options.babelOptions.ignore,
+    only: options.babelOptions.only,
+    parserOpts: {
+      allowImportExportEverywhere: options.allowImportExportEverywhere,
+      allowReturnOutsideFunction: true,
+      allowSuperOutsideMethod: true,
+      ranges: true,
+      tokens: true,
+      plugins: ["estree"],
+    },
+    caller: {
+      name: "@babel/eslint-parser",
+    },
+  };
+
+  if (options.requireConfigFile !== false) {
+    const config = loadPartialConfig(parseOptions);
+
+    if (config !== null) {
+      if (!config.hasFilesystemConfig()) {
+        throw new Error(
+          `No Babel config file detected for ${config.options.filename}. Either disable config file checking with requireConfigFile: false, or configure Babel so that it can find the config files.`,
+        );
+      }
+
+      return config.options;
+    }
+  }
+
+  return parseOptions;
+}

eslint/babel-eslint-parser/src/index.js

@@ -1,6 +1,7 @@
 import semver from "semver";
 import { version as CURRENT_BABEL_VERSION } from "@babel/core";
 import parseWithScope from "./parse-with-scope";
+import { normalizeESLintConfig } from "./configuration";
 import packageJson from "../package.json";
 
 const SUPPORTED_BABEL_VERSION_RANGE =
@@ -21,11 +22,5 @@ export function parseForESLint(code, options = {}) {
     );
   }
 
-  options.babelOptions = options.babelOptions || {};
-  options.ecmaVersion = options.ecmaVersion || 2018;
-  options.sourceType = options.sourceType || "module";
-  options.allowImportExportEverywhere =
-    options.allowImportExportEverywhere || false;
-
-  return parseWithScope(code, options);
+  return parseWithScope(code, normalizeESLintConfig(options));
 }

eslint/babel-eslint-parser/src/parse.js

@@ -1,61 +1,13 @@
+import { parseSync as babelParse, tokTypes as tt, traverse } from "@babel/core";
 import babylonToEspree from "./babylon-to-espree";
-import {
-  parseSync as parse,
-  tokTypes as tt,
-  traverse,
-  loadPartialConfig,
-} from "@babel/core";
-
-export default function(code, options) {
-  let opts = {
-    sourceType: options.sourceType,
-    filename: options.filePath,
-    cwd: options.babelOptions.cwd,
-    root: options.babelOptions.root,
-    rootMode: options.babelOptions.rootMode,
-    envName: options.babelOptions.envName,
-    configFile: options.babelOptions.configFile,
-    babelrc: options.babelOptions.babelrc,
-    babelrcRoots: options.babelOptions.babelrcRoots,
-    extends: options.babelOptions.extends,
-    env: options.babelOptions.env,
-    overrides: options.babelOptions.overrides,
-    test: options.babelOptions.test,
-    include: options.babelOptions.include,
-    exclude: options.babelOptions.exclude,
-    ignore: options.babelOptions.ignore,
-    only: options.babelOptions.only,
-    parserOpts: {
-      allowImportExportEverywhere: options.allowImportExportEverywhere, // consistent with espree
-      allowReturnOutsideFunction: true,
-      allowSuperOutsideMethod: true,
-      ranges: true,
-      tokens: true,
-      plugins: ["estree"],
-    },
-    caller: {
-      name: "@babel/eslint-parser",
-    },
-  };
-
-  if (options.requireConfigFile !== false) {
-    const config = loadPartialConfig(opts);
-
-    if (config !== null) {
-      if (!config.hasFilesystemConfig()) {
-        throw new Error(
-          `No Babel config file detected for ${config.options.filename}. Either disable config file checking with requireConfigFile: false, or configure Babel so that it can find the config files.`,
-        );
-      }
-
-      opts = config.options;
-    }
-  }
+import { normalizeBabelParseConfig } from "./configuration";
 
+export default function parse(code, options) {
+  const parseOptions = normalizeBabelParseConfig(options);
   let ast;
 
   try {
-    ast = parse(code, opts);
+    ast = babelParse(code, parseOptions);
   } catch (err) {
     if (err instanceof SyntaxError) {
       err.lineNumber = err.loc.line;

eslint/babel-eslint-parser/test/non-regression.js

@@ -1614,7 +1614,7 @@ describe("verify", () => {
       "var leakedGlobal = 1;",
       { "no-implicit-globals": 1 },
       [],
-      null,
+      undefined,
       {
         env: {},
         parserOptions: { ecmaVersion: 6 },