feat: support transpiled transformers (#11193)

Author: SimenB

CHANGELOG.md

@@ -26,6 +26,7 @@
 - `[jest-transform]` Add support for transformers written in ESM ([#11163](https://github.com/facebook/jest/pull/11163))
 - `[jest-transform]` [**BREAKING**] Do not export `ScriptTransformer` class, instead export the async function `createScriptTransformer` ([#11163](https://github.com/facebook/jest/pull/11163))
 - `[jest-transform]` Async code transformations ([#9889](https://github.com/facebook/jest/pull/9889))
+- `[jest-transform]` Support transpiled transformers ([#11193](https://github.com/facebook/jest/pull/11193))
 - `[jest-worker]` Add support for custom task queues and adds a `PriorityQueue` implementation. ([#10921](https://github.com/facebook/jest/pull/10921))
 - `[jest-worker]` Add in-order scheduling policy to jest worker ([10902](https://github.com/facebook/jest/pull/10902))
 
@@ -73,6 +74,7 @@
 - `[*]` [**BREAKING**] Add `exports` field to all `package.json`s ([#9921](https://github.com/facebook/jest/pull/9921))
 - `[*]` Make it easier for Jest's packages to use the VM escape hatch ([#10824](https://github.com/facebook/jest/pull/10824))
 - `[*]` [**BREAKING**] Remove deprecated `mapCoverage` ([#9968](https://github.com/facebook/jest/pull/9968))
+- `[babel-jest]` [**BREAKING**] Migrate to ESM ([#11193](https://github.com/facebook/jest/pull/11193))
 - `[docs]` Correct example using `browser-resolve` ([#11140](https://github.com/facebook/jest/pull/11140))
 - `[jest-config]` [**BREAKING**] Remove `enabledTestsMap` config, use `filter` instead ([#10787](https://github.com/facebook/jest/pull/10787))
 - `[jest-console]` [**BREAKING**] Move `root` into `config` and take `GlobalConfig` as mandatory parameter for `getConsoleOutput` ([#10126](https://github.com/facebook/jest/pull/10126))

e2e/__tests__/__snapshots__/transform.test.ts.snap

@@ -6,7 +6,7 @@ FAIL __tests__/ignoredFile.test.js
 
     babel-jest: Babel ignores __tests__/ignoredFile.test.js - make sure to include the file in Jest's transformIgnorePatterns as well.
 
-      at loadBabelConfig (../../../packages/babel-jest/build/index.js:190:13)
+      at loadBabelConfig (../../../packages/babel-jest/build/index.js:195:13)
 `;
 
 exports[`babel-jest instruments only specific files and collects coverage 1`] = `

e2e/transform/babel-jest-manual/transformer.js

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-const {createTransformer} = require('babel-jest');
+const {createTransformer} = require('babel-jest').default;
 
 module.exports = createTransformer({
   presets: ['@babel/preset-flow'],

packages/babel-jest/src/__tests__/index.ts

@@ -6,7 +6,7 @@
  */
 
 import {makeProjectConfig} from '@jest/test-utils';
-import babelJest = require('../index');
+import babelJest from '../index';
 import {loadPartialConfig} from '../loadBabelConfig';
 
 jest.mock('../loadBabelConfig', () => {

packages/babel-jest/src/index.ts

@@ -167,4 +167,4 @@ const transformer: SyncTransformer<TransformOptions> = {
   createTransformer,
 };
 
-export = transformer;
+export default transformer;

packages/jest-repl/src/__tests__/jest_repl.test.js

@@ -5,7 +5,6 @@
  * LICENSE file in the root directory of this source tree.
  *
  */
-'use strict';
 
 import {spawnSync} from 'child_process';
 import path from 'path';
@@ -29,6 +28,7 @@ describe('Repl', () => {
         encoding: 'utf8',
         env: process.env,
       });
+      expect(output.stderr.trim()).toBe('');
       expect(output.stdout.trim()).toMatch(/›/);
     });
   });

packages/jest-repl/src/cli/repl.ts

@@ -13,6 +13,7 @@ import * as repl from 'repl';
 import {runInThisContext} from 'vm';
 import type {SyncTransformer} from '@jest/transform';
 import type {Config} from '@jest/types';
+import {interopRequireDefault} from 'jest-util';
 
 // TODO: support async as well
 let transformer: SyncTransformer;
@@ -77,7 +78,7 @@ if (jestProjectConfig.transform) {
     }
   }
   if (transformerPath) {
-    transformer = require(transformerPath);
+    transformer = interopRequireDefault(require(transformerPath)).default;
     if (typeof transformer.process !== 'function') {
       throw new TypeError(
         'Jest: a transformer must export a `process` function.',

packages/jest-transform/src/ScriptTransformer.ts

@@ -255,7 +255,7 @@ class ScriptTransformer {
           let transformer: Transformer;
 
           try {
-            transformer = require(transformPath);
+            transformer = interopRequireDefault(require(transformPath)).default;
           } catch (error) {
             if (error.code === 'ERR_REQUIRE_ESM') {
               const configUrl = pathToFileURL(transformPath);