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nicolo-ribaudoliuxingbaoyu
nicolo-ribaudo
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liuxingbaoyu
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Improve CJS compat with ESM-based @babel/core (#15137)
Co-authored-by: liuxingbaoyu <30521560+liuxingbaoyu@users.noreply.github.com>
1 parent 43dce19 commit ca52e08

16 files changed

Lines changed: 286 additions & 5 deletions

‎babel.config.js‎

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Original file line numberDiff line numberDiff line change
@@ -231,6 +231,11 @@ module.exports = function (api) {
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{ name: "USE_ESM", value: outputType === "module" },
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"flag-USE_ESM",
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],
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[
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pluginToggleBooleanFlag,
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{ name: "IS_STANDALONE", value: env === "standalone" },
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"flag-IS_STANDALONE",
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],
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process.env.STRIP_BABEL_8_FLAG && [
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pluginToggleBooleanFlag,

‎packages/babel-core/cjs-proxy.cjs‎

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@@ -1,6 +1,12 @@
11
"use strict";
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33
const babelP = import("./lib/index.js");
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let babel = null;
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Object.defineProperty(exports, "__ initialize @babel/core cjs proxy __", {
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set(val) {
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babel = val;
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},
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});
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const functionNames = [
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"createConfigItem",
@@ -11,13 +17,9 @@ const functionNames = [
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"transformFromAst",
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"parse",
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];
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const propertyNames = ["types", "tokTypes", "traverse", "template", "version"];
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for (const name of functionNames) {
16-
exports[`${name}Sync`] = function () {
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throw new Error(
18-
`"${name}Sync" is not supported when loading @babel/core using require()`
19-
);
20-
};
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exports[name] = function (...args) {
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babelP.then(babel => {
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babel[name](...args);
@@ -26,4 +28,24 @@ for (const name of functionNames) {
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exports[`${name}Async`] = function (...args) {
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return babelP.then(babel => babel[`${name}Async`](...args));
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};
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exports[`${name}Sync`] = function (...args) {
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if (!babel) throw notLoadedError(`${name}Sync`, "callable");
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return babel[`${name}Sync`](...args);
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};
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}
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for (const name of propertyNames) {
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Object.defineProperty(exports, name, {
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get() {
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if (!babel) throw notLoadedError(name, "accessible");
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return babel[name];
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},
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});
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}
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function notLoadedError(name, keyword) {
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return new Error(
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`The \`${name}\` export of @babel/core is only ${keyword}` +
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` from the CommonJS version after that the ESM version is loaded.`
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);
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}

‎packages/babel-core/src/index.ts‎

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Original file line numberDiff line numberDiff line change
@@ -1,4 +1,6 @@
11
declare const PACKAGE_JSON: { name: string; version: string };
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declare const USE_ESM: boolean, IS_STANDALONE: boolean;
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24
export const version = PACKAGE_JSON.version;
35

46
export { default as File } from "./transformation/file/file";
@@ -72,15 +74,27 @@ export const DEFAULT_EXTENSIONS = Object.freeze([
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] as const);
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// For easier backward-compatibility, provide an API like the one we exposed in Babel 6.
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// TODO(Babel 8): Remove this.
7578
import { loadOptionsSync } from "./config";
7679
export class OptionManager {
7780
init(opts: {}) {
7881
return loadOptionsSync(opts);
7982
}
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}
8184

85+
// TODO(Babel 8): Remove this.
8286
export function Plugin(alias: string) {
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throw new Error(
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`The (${alias}) Babel 5 plugin is being run with an unsupported Babel version.`,
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);
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}
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import Module from "module";
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import * as thisFile from "./index";
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if (USE_ESM) {
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if (!IS_STANDALONE) {
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// Pass this module to the CJS proxy, so that it can be synchronously accessed.
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const cjsProxy = Module.createRequire(import.meta.url)("../cjs-proxy.cjs");
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cjsProxy["__ initialize @babel/core cjs proxy __"] = thisFile;
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}
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}

‎packages/babel-core/test/esm-cjs-integration.js‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,109 @@
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import { execFile } from "child_process";
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import { createRequire } from "module";
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import { outputType } from "./helpers/esm.js";
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const require = createRequire(import.meta.url);
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async function run(name) {
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return new Promise((res, rej) => {
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execFile(
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process.execPath,
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[require.resolve(`./fixtures/esm-cjs-integration/${name}`)],
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{ env: process.env },
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(error, stdout, stderr) => {
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if (error) rej(error);
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res({ stdout: stdout.toString(), stderr: stderr.toString() });
16+
},
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);
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});
19+
}
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(outputType === "module" ? describe : describe.skip)("usage from cjs", () => {
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it("lazy plugin required", async () => {
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expect(await run("lazy-plugin-required.cjs")).toMatchInlineSnapshot(`
24+
Object {
25+
"stderr": "",
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"stdout": "\\"Replaced!\\";
27+
",
28+
}
29+
`);
30+
});
31+
32+
it("lazy plugin as config string", async () => {
33+
expect(await run("lazy-plugin-as-string.cjs")).toMatchInlineSnapshot(`
34+
Object {
35+
"stderr": "",
36+
"stdout": "\\"Replaced!\\";
37+
",
38+
}
39+
`);
40+
});
41+
42+
it("eager plugin required", async () => {
43+
await expect(run("eager-plugin-required.cjs")).rejects.toThrow(
44+
"The `types` export of @babel/core is only accessible from" +
45+
" the CommonJS version after that the ESM version is loaded.",
46+
);
47+
});
48+
49+
it("eager plugin required after dynamic esm import", async () => {
50+
expect(await run("eager-plugin-required-after-dynamic-esm-import.cjs"))
51+
.toMatchInlineSnapshot(`
52+
Object {
53+
"stderr": "",
54+
"stdout": "\\"Replaced!\\";
55+
",
56+
}
57+
`);
58+
});
59+
60+
it("eager plugin required after static esm import", async () => {
61+
expect(await run("eager-plugin-required-after-static-esm-import.mjs"))
62+
.toMatchInlineSnapshot(`
63+
Object {
64+
"stderr": "",
65+
"stdout": "\\"Replaced!\\";
66+
",
67+
}
68+
`);
69+
});
70+
71+
it("eager plugin as config string", async () => {
72+
expect(await run("eager-plugin-as-string.cjs")).toMatchInlineSnapshot(`
73+
Object {
74+
"stderr": "",
75+
"stdout": "\\"Replaced!\\";
76+
",
77+
}
78+
`);
79+
});
80+
81+
it("transformSync", async () => {
82+
await expect(run("transform-sync.cjs")).rejects.toThrow(
83+
"The `transformSync` export of @babel/core is only callable from" +
84+
" the CommonJS version after that the ESM version is loaded.",
85+
);
86+
});
87+
88+
it("transformSync after dynamic esm import", async () => {
89+
expect(await run("transform-sync-after-dynamic-esm-import.cjs"))
90+
.toMatchInlineSnapshot(`
91+
Object {
92+
"stderr": "",
93+
"stdout": "REPLACE_ME;
94+
",
95+
}
96+
`);
97+
});
98+
99+
it("transformSync after static esm import", async () => {
100+
expect(await run("transform-sync-after-static-esm-import.mjs"))
101+
.toMatchInlineSnapshot(`
102+
Object {
103+
"stderr": "",
104+
"stdout": "REPLACE_ME;
105+
",
106+
}
107+
`);
108+
});
109+
});

‎packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-as-string.cjs‎

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@@ -0,0 +1,8 @@
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const babel = require("../../../cjs-proxy.cjs");
2+
3+
babel
4+
.transformAsync("REPLACE_ME;", {
5+
configFile: false,
6+
plugins: [__dirname + "/plugins/eager.cjs"],
7+
})
8+
.then(out => console.log(out.code), console.error);

‎packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-required-after-dynamic-esm-import.cjs‎

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1+
import("../../../lib/index.js")
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.then(babel =>
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babel.transformAsync("REPLACE_ME;", {
4+
configFile: false,
5+
plugins: [require("./plugins/eager.cjs")],
6+
}),
7+
)
8+
.then(out => console.log(out.code), console.error);

‎packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-required-after-static-esm-import.mjs‎

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import * as babel from "../../../lib/index.js";
2+
3+
babel
4+
.transformAsync("REPLACE_ME;", {
5+
configFile: false,
6+
plugins: [(await import("./plugins/eager.cjs")).default],
7+
})
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.then(out => console.log(out.code), console.error);

‎packages/babel-core/test/fixtures/esm-cjs-integration/eager-plugin-required.cjs‎

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/*
2+
* This test throws an error, because the plugin accesses
3+
* @babel/core's CJS .types export before that the ESM
4+
* version is loaded.
5+
*/
6+
7+
const babel = require("../../../cjs-proxy.cjs");
8+
9+
babel
10+
.transformAsync("REPLACE_ME;", {
11+
configFile: false,
12+
plugins: [require("./plugins/eager.cjs")],
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})
14+
.then(out => console.log(out.code), console.error);

‎packages/babel-core/test/fixtures/esm-cjs-integration/lazy-plugin-as-string.cjs‎

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const babel = require("../../../cjs-proxy.cjs");
2+
3+
babel
4+
.transformAsync("REPLACE_ME;", {
5+
configFile: false,
6+
plugins: [__dirname + "/plugins/lazy.cjs"],
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})
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.then(out => console.log(out.code), console.error);

‎packages/babel-core/test/fixtures/esm-cjs-integration/lazy-plugin-required.cjs‎

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const babel = require("../../../cjs-proxy.cjs");
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3+
babel
4+
.transformAsync("REPLACE_ME;", {
5+
configFile: false,
6+
plugins: [require("./plugins/lazy.cjs")],
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})
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.then(out => console.log(out.code), console.error);

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