Support Babel 8 alongside Babel 7

.eslintrc.js

@@ -28,7 +28,8 @@ module.exports = {
         'blueprints/*/index.js',
         'config/**/*.js',
         'tests/dummy/config/**/*.js',
-        'lib/**/*.js'
+        'lib/**/*.js',
+        'scripts/**/*.js'
       ],
       excludedFiles: [
         'addon/**',

.github/workflows/ci.yml

@@ -52,6 +52,25 @@ jobs:
     - name: test
       run: pnpm test:node
 
+  node-tests-babel-8:
+    name: "Node: Babel 8"
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+    - uses: actions/checkout@v6
+    - uses: pnpm/action-setup@v4
+    - uses: actions/setup-node@v6
+      with:
+        node-version: 20
+        cache: pnpm
+    - name: pin dependencies to Babel 8
+      run: node scripts/use-babel-8.js
+    - name: install dependencies
+      run: pnpm install --no-frozen-lockfile
+    - name: test
+      run: pnpm test:node
+
   acceptance-tests:
     name: "Acceptance: Node ${{ matrix.node }} - ${{ matrix.os }}"
     runs-on: "${{matrix.os}}-latest"

README.md

@@ -357,6 +357,22 @@ If you want to use the existing babel config from your project instead of the au
 
 *Note: If you are using this option, then you have to make sure that you are adding all of the required plugins required for Ember to transpile correctly.*
 
+*Note for Babel 8:* Babel 8 removed the root-level `moduleIds` and `getModuleId` options, which is how ember-cli-babel used to name your AMD modules. On Babel 8 they have to be passed to `@babel/plugin-transform-modules-amd` itself. `buildEmberPlugins` (below) already does this for you; if you configure the AMD transform by hand, name your modules like this:
+
+```js
+[
+  require.resolve("@babel/plugin-transform-modules-amd"),
+  {
+    noInterop: true,
+    moduleIds: true,
+    getModuleId: require("ember-cli-babel/lib/relative-module-paths")
+      .getRelativeModulePath,
+  },
+],
+```
+
+Without it your modules are emitted as anonymous `define([...])` calls and the Ember loader will not find them.
+
 Example usage:
 
 ```js
@@ -389,6 +405,8 @@ module.exports = function (api) {
     ],
     plugins: [
       // if you want external helpers
+      // On Babel 8, drop `regenerator` and `useESModules`: both options were
+      // removed, and @babel/runtime now resolves ESM helpers via its `exports`.
       [
         require.resolve("@babel/plugin-transform-runtime"),
         {

index.js

@@ -7,6 +7,8 @@ const {
   _getExtensions,
   _parentName,
   _shouldHighlightCode,
+  _getHelpersPlugin,
+  _babelCoreMajorVersion,
 } = require("./lib/babel-options-util");
 
 const VersionChecker = require('ember-cli-version-checker');
@@ -64,7 +66,9 @@ module.exports = {
     if (shouldUseBabelConfigFile) {
       const babel = require('@babel/core');
 
-      let babelConfig = babel.loadPartialConfig({
+      // Babel 8's `loadPartialConfig` is callback-based; the explicit sync
+      // variant has been available since Babel 7.8.
+      let babelConfig = babel.loadPartialConfigSync({
         root: this.parent.root,
         rootMode: 'root',
         envName: process.env.EMBER_ENV || process.env.BABEL_ENV || process.env.NODE_ENV || "development",
@@ -138,7 +142,11 @@ module.exports = {
       plugins: [],
     };
 
-    if (shouldCompileModules) {
+    // Babel 8 rejects these as unknown root options, so there the plugin-level
+    // values set by `_getModulesPlugin` are the only ones that apply. Babel 7
+    // still honors the root level, and `useBabelConfig` users depend on it
+    // because their own config supplies the module transform.
+    if (shouldCompileModules && _babelCoreMajorVersion() < 8) {
       options.moduleIds = true;
       options.getModuleId = require("./lib/relative-module-paths").getRelativeModulePath;
     }
@@ -230,16 +238,7 @@ module.exports = {
   },
 
   _getHelpersPlugin() {
-    return [
-      [
-        require.resolve('@babel/plugin-transform-runtime'),
-        {
-          version: this._getHelperVersion(),
-          regenerator: false,
-          useESModules: true
-        }
-      ]
-    ]
+    return _getHelpersPlugin(this.project);
   },
 
   treeForAddon() {

lib/babel-options-util.js

@@ -11,6 +11,13 @@ const defaultShouldIncludeHelpers = require("./default-should-include-helpers");
 /**
  * This util contains private functions required for generating babel options.
  */
+
+// Resolved rather than assumed, since `@babel/core` is a peer dependency and
+// several plugin options differ between Babel 7 and 8.
+function _babelCoreMajorVersion() {
+  return semver.major(require("@babel/core/package.json").version);
+}
+
 function _getPresetEnv(config, project) {
   let options = config.options;
 
@@ -31,14 +38,23 @@ function _getPresetEnv(config, project) {
 }
 
 function _getModulesPlugin() {
-  const resolvePath = require("./relative-module-paths")
-    .resolveRelativeModulePath;
+  const {
+    resolveRelativeModulePath: resolvePath,
+    getRelativeModulePath: getModuleId,
+  } = require("./relative-module-paths");
 
   return [
     [require.resolve("babel-plugin-module-resolver"), { resolvePath }],
     [
       require.resolve("@babel/plugin-transform-modules-amd"),
-      { noInterop: true },
+      {
+        noInterop: true,
+        // Babel 8 dropped the root-level `moduleIds`/`getModuleId` options; the
+        // module transform reads them from its own options instead. Babel 7
+        // already prefers the plugin-level values, so this works on both.
+        moduleIds: true,
+        getModuleId,
+      },
     ],
   ];
 }
@@ -274,16 +290,17 @@ function _getEmberDataPackagesPolyfill(config, parent) {
   }
 }
 function _getHelpersPlugin(project) {
-  return [
-    [
-      require.resolve("@babel/plugin-transform-runtime"),
-      {
-        version: _getHelperVersion(project),
-        regenerator: false,
-        useESModules: true,
-      },
-    ],
-  ];
+  const options = { version: _getHelperVersion(project) };
+
+  if (_babelCoreMajorVersion() < 8) {
+    // Both options were removed in Babel 8: generators no longer depend on a
+    // `regeneratorRuntime` global, and @babel/runtime exposes its ESM helpers
+    // through package.json#exports.
+    options.regenerator = false;
+    options.useESModules = true;
+  }
+
+  return [[require.resolve("@babel/plugin-transform-runtime"), options]];
 }
 function _getHelperVersion(project) {
   if (!APP_BABEL_RUNTIME_VERSION.has(project)) {
@@ -345,7 +362,9 @@ function _addDecoratorPlugins(plugins, options, config, parent, project) {
   } else {
     addPlugin(
       plugins,
-      [require.resolve("@babel/plugin-proposal-decorators"), { legacy: true }],
+      // `legacy: true` was removed in Babel 8; `version: "legacy"` is the
+      // equivalent and is understood by Babel 7 as well.
+      [require.resolve("@babel/plugin-proposal-decorators"), { version: "legacy" }],
       _buildClassFeaturePluginConstraints(
         {
           before: ["@babel/plugin-transform-class-properties"],
@@ -625,6 +644,7 @@ function _shouldIncludeHelpers(options, appInstance) {
 }
 
 module.exports = {
+  _babelCoreMajorVersion,
   _addDecoratorPlugins,
   _addTypeScriptPlugin,
   _getAddonProvidedConfig,

lib/ember-plugins.js

@@ -147,13 +147,23 @@ function _getEmberDataPackagesPolyfill(appRoot, config) {
 
 function _getModuleResolutionPlugins(config) {
   if (!config.disableModuleResolution) {
-    const resolvePath = require("../lib/relative-module-paths")
-      .resolveRelativeModulePath;
+    const {
+      resolveRelativeModulePath: resolvePath,
+      getRelativeModulePath: getModuleId,
+    } = require("../lib/relative-module-paths");
+
     return [
       [require.resolve("babel-plugin-module-resolver"), { resolvePath }],
       [
         require.resolve("@babel/plugin-transform-modules-amd"),
-        { noInterop: true },
+        {
+          noInterop: true,
+          // Babel 8 only reads `moduleIds`/`getModuleId` from the module
+          // transform's own options, not from the root config. Babel 7 prefers
+          // the plugin-level values too, so this is correct on both.
+          moduleIds: true,
+          getModuleId,
+        },
       ],
     ];
   }
@@ -173,7 +183,7 @@ function _getProposalDecoratorsAndClassPlugins(config) {
       * we need to compile it away.
       */
       ["@babel/plugin-transform-class-static-block"],
-      ["@babel/plugin-proposal-decorators", { legacy: true }],
+      ["@babel/plugin-proposal-decorators", { version: "legacy" }],
       ["@babel/plugin-transform-class-properties"],
     ];
   }

node-tests/addon-test.js

@@ -23,7 +23,8 @@ const {
   _shouldHandleTypeScript,
   _shouldIncludeHelpers,
   _shouldCompileModules,
-  _getExtensions
+  _getExtensions,
+  _babelCoreMajorVersion
 } = require("../lib/babel-options-util");
 
 const { codeEquality } = require("code-equality-assertions/chai");
@@ -153,6 +154,18 @@ describe('ember-cli-babel', function() {
         const result = output.read();
 
         expect(Object.keys(result)).to.deep.equal(['foo.js']);
+
+        // Babel 8 emits the same inline helpers in a different order, so the
+        // exact-output snapshot below only holds on Babel 7. What this test is
+        // really about is that the static block is compiled away, which is
+        // asserted for both.
+        expect(result['foo.js']).to.include('_Second.bar = 1');
+        expect(result['foo.js']).to.not.include('static {');
+
+        if (_babelCoreMajorVersion() >= 8) {
+          return;
+        }
+
         expect(result['foo.js']).to.equalCode(`function _typeof(o) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (o) { return typeof o; } : function (o) { return o && "function" == typeof Symbol && o.constructor === Symbol && o !== Symbol.prototype ? "symbol" : typeof o; }, _typeof(o); }
 define("foo", [], function () {
   "use strict";
@@ -1698,13 +1711,32 @@ define("foo", [], function () {
   describe('buildBabelOptions', function() {
     this.timeout(0);
 
+    // Module ids always live on the AMD transform's own options. Babel 7 also
+    // honors them at the root, but Babel 8 rejects unknown root options, so we
+    // only emit them there on 7.
+    function expectModuleIdsConfigured(result) {
+      let amdPlugin = result.plugins.find(
+        plugin => Array.isArray(plugin) && /plugin-transform-modules-amd/.test(plugin[0])
+      );
+
+      expect(amdPlugin, 'AMD transform is present').to.exist;
+      expect(amdPlugin[1].moduleIds).to.be.true;
+      expect(amdPlugin[1].getModuleId).to.be.a('function');
+
+      if (_babelCoreMajorVersion() < 8) {
+        expect(result.moduleIds).to.be.true;
+      } else {
+        expect('moduleIds' in result).to.be.false;
+      }
+    }
+
     it('returns broccoli-babel-transpiler options by default', function() {
       this.addon.parent = { ...this.addon.parent, name: 'foo' };
 
       let result = this.addon.buildBabelOptions();
 
       expect(result.annotation).to.equal('Babel: foo');
-      expect(result.moduleIds).to.be.true;
+      expectModuleIdsConfigured(result);
       expect(result.babelrc).to.be.false;
       expect(result.configFile).to.be.false;
     });
@@ -1715,7 +1747,7 @@ define("foo", [], function () {
       let result = this.addon.buildBabelOptions('broccoli');
 
       expect(result.annotation).to.equal('Babel: foo');
-      expect(result.moduleIds).to.be.true;
+      expectModuleIdsConfigured(result);
       expect(result.babelrc).to.be.false;
       expect(result.configFile).to.be.false;
     });
@@ -1728,7 +1760,7 @@ define("foo", [], function () {
       });
 
       expect(result.annotation).to.equal('hello!!!');
-      expect(result.moduleIds).to.be.true;
+      expectModuleIdsConfigured(result);
       expect(result.babelrc).to.be.false;
       expect(result.configFile).to.be.false;
     });
@@ -2320,9 +2352,16 @@ describe('babel config file', function() {
   }));
 
   it("should transpile to amd modules based on babel config", co.wrap(function* () {
+    // On Babel 7 ember-cli-babel supplies `moduleIds`/`getModuleId` at the root
+    // of the Babel config. Babel 8 removed those root options, so a project
+    // bringing its own babel config has to pass them to the AMD transform.
+    let moduleIdOptions = _babelCoreMajorVersion() < 8 ? '' : `
+      moduleIds: true,
+      getModuleId: require("ember-cli-babel/lib/relative-module-paths").getRelativeModulePath,`;
+
     yield setupForVersion(`[
       require.resolve("@babel/plugin-transform-modules-amd"),
-      { noInterop: true },
+      { noInterop: true,${moduleIdOptions} },
     ]`);
     input.write({
       "foo.js": `export default {};`,

package.json

@@ -40,16 +40,16 @@
     "test:node:debug": "mocha debug node-tests"
   },
   "dependencies": {
-    "@babel/helper-compilation-targets": "^7.20.7",
-    "@babel/plugin-proposal-decorators": "^7.20.13",
-    "@babel/plugin-transform-class-properties": "^7.16.5",
-    "@babel/plugin-transform-class-static-block": "^7.22.11",
-    "@babel/plugin-transform-modules-amd": "^7.20.11",
-    "@babel/plugin-transform-private-methods": "^7.16.5",
-    "@babel/plugin-transform-private-property-in-object": "^7.20.5",
-    "@babel/plugin-transform-runtime": "^7.13.9",
-    "@babel/plugin-transform-typescript": "^7.20.13",
-    "@babel/preset-env": "^7.20.2",
+    "@babel/helper-compilation-targets": "^7.20.7 || ^8.0.0",
+    "@babel/plugin-proposal-decorators": "^7.20.13 || ^8.0.0",
+    "@babel/plugin-transform-class-properties": "^7.16.5 || ^8.0.0",
+    "@babel/plugin-transform-class-static-block": "^7.22.11 || ^8.0.0",
+    "@babel/plugin-transform-modules-amd": "^7.20.11 || ^8.0.0",
+    "@babel/plugin-transform-private-methods": "^7.16.5 || ^8.0.0",
+    "@babel/plugin-transform-private-property-in-object": "^7.20.5 || ^8.0.0",
+    "@babel/plugin-transform-runtime": "^7.13.9 || ^8.0.0",
+    "@babel/plugin-transform-typescript": "^7.20.13 || ^8.0.0",
+    "@babel/preset-env": "^7.20.2 || ^8.0.0",
     "@babel/runtime": "7.12.18",
     "amd-name-resolver": "^1.3.1",
     "babel-plugin-debug-macros": "^0.3.4",
@@ -108,7 +108,7 @@
     "webpack": "^5.88.2"
   },
   "peerDependencies": {
-    "@babel/core": "^7.12.0"
+    "@babel/core": "^7.12.0 || ^8.0.0"
   },
   "packageManager": "pnpm@8.15.9",
   "engines": {