Use native esm for babel config and babel custom plugin

.eslintrc.cjs

@@ -324,7 +324,7 @@ module.exports = {
           '**/__typetests__/**',
           '**/?(*.)(spec|test).js?(x)',
           'scripts/**',
-          'babel.config.js',
+          'babel.config.mjs',
           'testSetupFile.js',
           '.eslintrc.cjs',
         ],

babel.config.js → babel.config.mjs

@@ -5,20 +5,26 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-const semver = require('semver');
+import {createRequire} from 'module';
+import path from 'path';
+import {fileURLToPath} from 'url';
+import semver from 'semver';
+const require = createRequire(import.meta.url);
 const pkg = require('./package.json');
 
 const supportedNodeVersion = semver.minVersion(pkg.engines.node).version;
+const dirname = path.dirname(fileURLToPath(import.meta.url));
 
-module.exports = {
+export default {
   babelrcRoots: ['examples/*'],
   // we don't wanna run the transforms in this file over react native
   exclude: /react-native/,
   overrides: [
     {
       plugins: [
-        require.resolve(
-          './scripts/babel-plugin-jest-replace-ts-require-assignment.js',
+        path.resolve(
+          dirname,
+          'scripts/babel-plugin-jest-replace-ts-require-assignment.mjs',
         ),
       ],
       presets: [
@@ -37,7 +43,7 @@ module.exports = {
   ],
   plugins: [
     ['@babel/plugin-transform-modules-commonjs', {allowTopLevelThis: true}],
-    require.resolve('./scripts/babel-plugin-jest-require-outside-vm'),
+    path.resolve(dirname, 'scripts/babel-plugin-jest-require-outside-vm.mjs'),
   ],
   presets: [
     [

examples/mongodb/jest.config.js

@@ -11,5 +11,9 @@ module.exports = {
   // The test environment that will be used for testing
   testEnvironment: './mongo-environment.js',
 
+  transform: {
+    '\\.js$': [require.resolve('babel-jest'), {cwd: __dirname}],
+  },
+
   transformIgnorePatterns: ['/node_modules/', '/packages/'],
 };

examples/typescript/jest.config.js

@@ -0,0 +1,10 @@
+// For a detailed explanation regarding each configuration property, visit:
+// https://jestjs.io/docs/configuration
+
+module.exports = {
+  testEnvironment: 'jsdom',
+
+  transform: {
+    '\\.js$': [require.resolve('babel-jest'), {cwd: __dirname}],
+  },
+};

examples/typescript/package.json

@@ -18,8 +18,5 @@
   },
   "scripts": {
     "test": "jest"
-  },
-  "jest": {
-    "testEnvironment": "jsdom"
   }
 }

jest.config.mjs

@@ -70,7 +70,7 @@ export default {
   ],
   testTimeout: 70000,
   transform: {
-    '\\.[jt]sx?$': require.resolve('babel-jest'),
+    '\\.[jt]sx?$': '<rootDir>/transformer.mjs',
   },
   watchPathIgnorePatterns: ['coverage'],
   watchPlugins: [

scripts/babel-plugin-jest-native-globals.js → scripts/babel-plugin-jest-native-globals.mjs

@@ -5,12 +5,10 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-'use strict';
-
 // This plugin exists to make sure that we use a `Promise` that has not been messed with by user code.
 // Might consider extending this to other globals as well in the future
 
-module.exports = ({template}) => {
+export default ({template}) => {
   const promiseDeclaration = template(`
     var Promise = globalThis[Symbol.for('jest-native-promise')] || globalThis.Promise;
   `);

scripts/babel-plugin-jest-replace-ts-require-assignment.js → scripts/babel-plugin-jest-replace-ts-require-assignment.mjs

@@ -5,11 +5,9 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-'use strict';
-
 // Replace `import thing = require('thing')` with `const thing = require('thing')` which allows us to keep CJS semantics
 
-module.exports = ({template}) => {
+export default ({template}) => {
   const moduleExportsDeclaration = template(`
     import NAME from 'IMPORT';
   `);

scripts/babel-plugin-jest-require-outside-vm.js → scripts/babel-plugin-jest-require-outside-vm.mjs

@@ -5,9 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-'use strict';
-
-const assert = require('assert');
+import assert from 'assert';
 
 /*
 Replace
@@ -23,7 +21,7 @@ require(require.resolve('package', {
 
 const REQUIRE_OUTSIDE_FUNCTION_NAME = 'requireOutside';
 
-module.exports = ({template, types: t}) => {
+export default ({template, types: t}) => {
   const replacement = template(`
     require(require.resolve(IMPORT_PATH, {
       [(globalThis['jest-symbol-do-not-touch'] || globalThis.Symbol).for('jest-resolve-outside-vm-option')]: true,

scripts/build.mjs

@@ -25,7 +25,7 @@ import glob from 'glob';
 import fs from 'graceful-fs';
 import micromatch from 'micromatch';
 import prettier from 'prettier';
-import transformOptions from '../babel.config.js';
+import transformOptions from '../babel.config.mjs';
 import {
   OK,
   PACKAGES_DIR,
@@ -60,14 +60,16 @@ function getBuildPath(file, buildFolder) {
   return path.resolve(pkgBuildPath, relativeToSrcPath).replace(/\.ts$/, '.js');
 }
 
-function buildNodePackage({packageDir, pkg}) {
+async function buildNodePackage({packageDir, pkg}) {
   const srcDir = path.resolve(packageDir, SRC_DIR);
   const pattern = path.resolve(srcDir, '**/*');
   const files = glob.sync(pattern, {nodir: true});
 
   process.stdout.write(adjustToTerminalWidth(`${pkg.name}\n`));
 
-  files.forEach(file => buildFile(file, true));
+  for (const file of files) {
+    await buildFile(file, true);
+  }
 
   assert.ok(
     fs.existsSync(path.resolve(packageDir, pkg.main)),
@@ -77,7 +79,7 @@ function buildNodePackage({packageDir, pkg}) {
   process.stdout.write(`${OK}\n`);
 }
 
-function buildFile(file, silent) {
+async function buildFile(file, silent) {
   const destPath = getBuildPath(file, BUILD_DIR);
 
   if (micromatch.isMatch(file, IGNORE_PATTERN)) {
@@ -115,7 +117,7 @@ function buildFile(file, silent) {
       options.plugins.push(
         path.resolve(
           path.dirname(fileURLToPath(import.meta.url)),
-          'babel-plugin-jest-native-globals.js',
+          'babel-plugin-jest-native-globals.mjs',
         ),
       );
     } else {
@@ -131,7 +133,7 @@ function buildFile(file, silent) {
       });
     }
 
-    const transformed = babel.transformFileSync(file, options).code;
+    const {code: transformed} = await babel.transformFileAsync(file, options);
     const prettyCode = prettier.format(transformed, prettierConfig);
 
     fs.writeFileSync(destPath, prettyCode);
@@ -148,12 +150,20 @@ function buildFile(file, silent) {
   }
 }
 
-const files = process.argv.slice(2);
-
-if (files.length) {
-  files.forEach(file => buildFile(file));
-} else {
-  const packages = getPackages();
-  process.stdout.write(chalk.inverse(' Building packages \n'));
-  packages.forEach(buildNodePackage);
-}
+(async () => {
+  const files = process.argv.slice(2);
+  if (files.length) {
+    for (const file of files) {
+      await buildFile(file, true);
+    }
+  } else {
+    const packages = getPackages();
+    process.stdout.write(chalk.inverse(' Building packages \n'));
+    for (const pkg of packages) {
+      await buildNodePackage(pkg);
+    }
+  }
+})().catch(error => {
+  console.error('Got error', error.stack);
+  process.exitCode = 1;
+});

transformer.mjs

@@ -0,0 +1,17 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+import {fileURLToPath} from 'url';
+import {createTransformer} from 'babel-jest';
+
+export default {
+  ...createTransformer({
+    root: fileURLToPath(import.meta.url),
+  }),
+  // remove the synchronous functions
+  getCacheKey: undefined,
+  process: undefined,
+};