[babel 8] Remove unnecessary CJS ESM wrapper (#17261)

nicolo-ribaudo · web-flow · commit c19e00eb22fe · 2025-04-25T22:56:58.000+02:00
* [babel 8] Remove unnecessary CJS ESM wrapper

* Use latest Node.js for e2e test

* Add snapshot to test
diff --git a/.github/workflows/e2e-tests-breaking-esm.yml b/.github/workflows/e2e-tests-breaking-esm.yml
@@ -71,7 +71,7 @@ jobs:
       - name: Use Node.js latest
         uses: actions/setup-node@v4
         with:
-          node-version: "*"
+          node-version: latest
       - name: Get yarn cache directory path
         id: yarn-cache-dir-path
         run: echo "dir=$(yarn config get cacheFolder)" >> $GITHUB_OUTPUT
diff --git a/packages/babel-core/.npmignore b/packages/babel-core/.npmignore
@@ -3,4 +3,3 @@ test
 *.log
 tsconfig.json
 tsconfig.tsbuildinfo
-cjs-proxy-dev.cjs
diff --git a/packages/babel-core/cjs-proxy-dev.cjs b/packages/babel-core/cjs-proxy-dev.cjs
diff --git a/packages/babel-core/cjs-proxy.cjs b/packages/babel-core/cjs-proxy.cjs
diff --git a/packages/babel-core/package.json b/packages/babel-core/package.json
@@ -102,7 +102,6 @@
         "exports": {
           ".": {
             "types": "./lib/index.d.ts",
-            "require": "./cjs-proxy.cjs",
             "default": "./lib/index.js"
           },
           "./package.json": "./package.json"
@@ -116,7 +115,6 @@
   "exports": {
     ".": {
       "types": "./lib/index.d.ts",
-      "require": "./cjs-proxy-dev.cjs",
       "default": "./lib/index.js"
     },
     "./package.json": "./package.json"
diff --git a/packages/babel-core/src/index.ts b/packages/babel-core/src/index.ts
@@ -92,14 +92,6 @@ export const DEFAULT_EXTENSIONS = Object.freeze([
   ".cjs",
 ] as const);
 
-import Module from "node:module" with { if: "USE_ESM && !IS_STANDALONE" };
-import * as thisFile from "./index.ts" with { if: "USE_ESM && !IS_STANDALONE" };
-if (USE_ESM && !IS_STANDALONE) {
-  // Pass this module to the CJS proxy, so that it can be synchronously accessed.
-  const cjsProxy = Module.createRequire(import.meta.url)("../cjs-proxy.cjs");
-  cjsProxy["__ initialize @babel/core cjs proxy __"] = thisFile;
-}
-
 if (!process.env.BABEL_8_BREAKING && !USE_ESM) {
   // For easier backward-compatibility, provide an API like the one we exposed in Babel 6.
   // eslint-disable-next-line no-restricted-globals
diff --git a/packages/babel-core/test/api.js b/packages/babel-core/test/api.js
@@ -1039,7 +1039,7 @@ if (IS_BABEL_8() && USE_ESM) {
     it("error should be caught", () => {
       let err;
       try {
-        const cjs = require("../cjs-proxy.cjs");
+        const cjs = require("../lib/index.js");
         cjs.parse("foo");
       } catch (error) {
         err = error;
diff --git a/packages/babel-core/test/esm-cjs-integration.js b/packages/babel-core/test/esm-cjs-integration.js
@@ -52,10 +52,13 @@ describeESM("usage from cjs", () => {
   });
 
   it("eager plugin required", async () => {
-    await expect(run("eager-plugin-required.cjs")).rejects.toThrow(
-      "The `types` export of @babel/core is only accessible from" +
-        " the CommonJS version after that the ESM version is loaded.",
-    );
+    expect(await run("eager-plugin-required.cjs")).toMatchInlineSnapshot(`
+      Object {
+        "stderr": "",
+        "stdout": "\\"Replaced!\\";
+      ",
+      }
+    `);
   });
 
   it("eager plugin required after dynamic esm import", async () => {
@@ -91,10 +94,13 @@ describeESM("usage from cjs", () => {
   });
 
   it("transformSync", async () => {
-    await expect(run("transform-sync.cjs")).rejects.toThrow(
-      "The `transformSync` export of @babel/core is only callable from" +
-        " the CommonJS version after that the ESM version is loaded.",
-    );
+    expect(await run("transform-sync.cjs")).toMatchInlineSnapshot(`
+      Object {
+        "stderr": "",
+        "stdout": "REPLACE_ME;
+      ",
+      }
+    `);
   });
 
   it("transformSync after dynamic esm import", async () => {
@@ -141,9 +147,9 @@ describeESM("sync loading of ESM plugins", () => {
           "--experimental-require-module",
         );
         expect(stdout).toMatchInlineSnapshot(`
-        "\\"Replaced!\\";
-        "
-      `);
+            "\\"Replaced!\\";
+            "
+        `);
       });
 
       it("top-level await", async () => {
@@ -169,9 +175,9 @@ describeESM("sync loading of ESM plugins", () => {
           "--experimental-require-module",
         );
         expect(stdout).toMatchInlineSnapshot(`
-        "\\"Replaced!\\";
-        "
-      `);
+            "\\"Replaced!\\";
+            "
+        `);
       });
 
       it("top-level await with --experimental-require-module flag", async () => {
diff --git a/packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-as-string.cjs b/packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-as-string.cjs
@@ -1,4 +1,4 @@
-const babel = require("../../../cjs-proxy.cjs");
+const babel = require("../../../lib/index.js");
 
 babel
   .transformAsync("REPLACE_ME;", {
diff --git a/packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-required.cjs b/packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-required.cjs
@@ -4,7 +4,7 @@
  * version is loaded.
  */
 
-const babel = require("../../../cjs-proxy.cjs");
+const babel = require("../../../lib/index.js");
 
 babel
   .transformAsync("REPLACE_ME;", {
diff --git a/packages/babel-core/test/fixtures/esm-cjs-integration/lazy-plugin-as-string.cjs b/packages/babel-core/test/fixtures/esm-cjs-integration/lazy-plugin-as-string.cjs
@@ -1,4 +1,4 @@
-const babel = require("../../../cjs-proxy.cjs");
+const babel = require("../../../lib/index.js");
 
 babel
   .transformAsync("REPLACE_ME;", {
diff --git a/packages/babel-core/test/fixtures/esm-cjs-integration/lazy-plugin-required.cjs b/packages/babel-core/test/fixtures/esm-cjs-integration/lazy-plugin-required.cjs
@@ -1,4 +1,4 @@
-const babel = require("../../../cjs-proxy.cjs");
+const babel = require("../../../lib/index.js");
 
 babel
   .transformAsync("REPLACE_ME;", {
diff --git a/packages/babel-core/test/fixtures/esm-cjs-integration/plugins/eager.cjs b/packages/babel-core/test/fixtures/esm-cjs-integration/plugins/eager.cjs
@@ -1,4 +1,4 @@
-const { types: t } = require("../../../../cjs-proxy.cjs");
+const { types: t } = require("../../../../lib/index.js");
 
 module.exports = function () {
   return {
diff --git a/packages/babel-core/test/fixtures/esm-cjs-integration/plugins/lazy.cjs b/packages/babel-core/test/fixtures/esm-cjs-integration/plugins/lazy.cjs
@@ -1,5 +1,5 @@
 /*
-import { types as t } from "../../../../cjs-proxy.cjs";
+import { types as t } from "../../../../lib/index.js";
 
 export default function () {
   return {
@@ -20,7 +20,7 @@ Object.defineProperty(exports, "__esModule", {
   value: true,
 });
 exports["default"] = _default;
-var _core = require("../../../../cjs-proxy.cjs");
+var _core = require("../../../../lib/index.js");
 function _default() {
   return {
     visitor: {
diff --git a/packages/babel-core/test/fixtures/esm-cjs-integration/transform-sync.cjs b/packages/babel-core/test/fixtures/esm-cjs-integration/transform-sync.cjs
@@ -3,7 +3,7 @@
  * is called before that the ESM version is loaded.
  */
 
-const babel = require("../../../cjs-proxy.cjs");
+const babel = require("../../../lib/index.js");
 
 const out = babel.transformSync("REPLACE_ME;", { configFile: false });
 console.log(out.code);
diff --git a/scripts/generators/npm-ignore.js b/scripts/generators/npm-ignore.js
@@ -12,7 +12,6 @@ const commonIgnore = [
 ];
 
 const extraIgnore = {
-  "babel-core": ["cjs-proxy-dev.cjs"],
   "babel-plugin-proposal-decorators": ["CONTRIB.md"],
   "babel-compat-data": ["build"],
 };
diff --git a/yarn.config.cjs b/yarn.config.cjs
@@ -332,7 +332,6 @@ function enforceExports({ Yarn }) {
       [
         "@babel/compat-data",
         "@babel/helper-plugin-test-runner", // TODO: Remove in Babel 8
-        "@babel/core", // TODO: Remove in Babel 8
         "@babel/plugin-transform-react-jsx", // TODO: Remove in Babel 8
         "@babel/standalone",
         "@babel/types", // @babel/types has types exports

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-const babel = require("../../../cjs-proxy.cjs");`
	`1`	`+const babel = require("../../../lib/index.js");`
`2`	`2`
`3`	`3`	`babel`
`4`	`4`	`.transformAsync("REPLACE_ME;", {`