feat: bundle Jest's modules with webpack

CHANGELOG.md

@@ -15,6 +15,8 @@
 
 ### Performance
 
+- `[*]` [**BREAKING**] Bundle all of Jest's modules into `index.js` ([#12348](https://github.com/jestjs/jest/pull/12348))
+
 ### Chore & Maintenance
 
 - `[*]` [**BREAKING**] Drop support for Node.js versions 14 and 19 ([#14460](https://github.com/jestjs/jest/pull/14460))

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

@@ -16,7 +16,7 @@ exports[`defining tests and hooks asynchronously throws 1`] = `
       14 |   });
       15 | });
 
-      at eventHandler (../../packages/jest-circus/build/eventHandler.js:141:11)
+      at eventHandler (../../packages/jest-circus/build/jestAdapterInit.js:148:38)
       at test (__tests__/asyncDefinition.test.js:12:5)
 
   ● Test suite failed to run
@@ -31,7 +31,7 @@ exports[`defining tests and hooks asynchronously throws 1`] = `
       15 | });
       16 |
 
-      at eventHandler (../../packages/jest-circus/build/eventHandler.js:104:11)
+      at eventHandler (../../packages/jest-circus/build/jestAdapterInit.js:114:38)
       at afterAll (__tests__/asyncDefinition.test.js:13:5)
 
   ● Test suite failed to run
@@ -46,7 +46,7 @@ exports[`defining tests and hooks asynchronously throws 1`] = `
       20 | });
       21 |
 
-      at eventHandler (../../packages/jest-circus/build/eventHandler.js:141:11)
+      at eventHandler (../../packages/jest-circus/build/jestAdapterInit.js:148:38)
       at test (__tests__/asyncDefinition.test.js:18:3)
 
   ● Test suite failed to run
@@ -60,6 +60,6 @@ exports[`defining tests and hooks asynchronously throws 1`] = `
       20 | });
       21 |
 
-      at eventHandler (../../packages/jest-circus/build/eventHandler.js:104:11)
+      at eventHandler (../../packages/jest-circus/build/jestAdapterInit.js:114:38)
       at afterAll (__tests__/asyncDefinition.test.js:19:3)"
 `;

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

@@ -41,7 +41,7 @@ exports[`moduleNameMapper wrong array configuration 1`] = `
       12 | module.exports = () => 'test';
       13 |
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/resolver.js:759:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:1175:17)
       at Object.require (index.js:10:1)
       at Object.require (__tests__/index.js:10:20)"
 `;
@@ -71,7 +71,7 @@ exports[`moduleNameMapper wrong configuration 1`] = `
       12 | module.exports = () => 'test';
       13 |
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/resolver.js:759:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:1175:17)
       at Object.require (index.js:10:1)
       at Object.require (__tests__/index.js:10:20)"
 `;

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

@@ -26,7 +26,7 @@ exports[`shows a proper error from deep requires 1`] = `
       12 | test('dummy', () => {
       13 |   expect(1).toBe(1);
 
-      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/resolver.js:427:11)
+      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/index.js:930:11)
       at Object.<anonymous> (node_modules/discord.js/src/index.js:21:12)
       at Object.require (__tests__/test.js:10:1)"
 `;

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

@@ -37,7 +37,7 @@ exports[`show error message with matching files 1`] = `
         |                  ^
       9 |
 
-      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/resolver.js:427:11)
+      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/index.js:930:11)
       at Object.require (index.js:8:18)
       at Object.require (__tests__/test.js:8:11)"
 `;

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

@@ -77,7 +77,7 @@ exports[`--showConfig outputs config info and exits 1`] = `
         "/node_modules/"
       ],
       "testRegex": [],
-      "testRunner": "<<REPLACED_JEST_PACKAGES_DIR>>/jest-circus/runner.js",
+      "testRunner": "<<REPLACED_JEST_PACKAGES_DIR>>/jest-circus/build/runner.js",
       "transform": [
         [
           "\\\\.[jt]sx?$",

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

@@ -46,7 +46,7 @@ FAIL __tests__/worksWithConcurrentMode.test.js
       15 |   });
       16 |
 
-      at Function.failing (../../packages/jest-jasmine2/build/jasmineAsyncInstall.js:175:11)
+      at Function.failing (../../packages/jest-jasmine2/build/index.js:308:17)
       at Suite.failing (__tests__/worksWithConcurrentMode.test.js:13:17)
       at Object.describe (__tests__/worksWithConcurrentMode.test.js:8:1)
 
@@ -80,7 +80,7 @@ FAIL __tests__/worksWithConcurrentOnlyMode.test.js
       15 |   });
       16 |
 
-      at Function.failing (../../packages/jest-jasmine2/build/jasmineAsyncInstall.js:175:11)
+      at Function.failing (../../packages/jest-jasmine2/build/index.js:308:17)
       at Suite.failing (__tests__/worksWithConcurrentOnlyMode.test.js:13:22)
       at Object.describe (__tests__/worksWithConcurrentOnlyMode.test.js:8:1)
 

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

@@ -6,7 +6,7 @@ exports[`babel-jest ignored tells user to match ignored files 1`] = `
 
     babel-jest: Babel ignores __tests__/ignoredFile.test.js - make sure to include the file in Jest's transformIgnorePatterns as well.
 
-      at assertLoadedBabelConfig (../../../packages/babel-jest/build/index.js:105:11)"
+      at assertLoadedBabelConfig (../../../packages/babel-jest/build/index.js:138:11)"
 `;
 
 exports[`babel-jest instruments only specific files and collects coverage 1`] = `

e2e/__tests__/stackTrace.test.ts

@@ -81,7 +81,7 @@ describe('Stack Trace', () => {
     );
 
     expect(stderr).toMatch(
-      /\s+at\s(?:.+?)\s\((?:.+?)jest-resolve\/build\/resolver\.js/,
+      /\s+at\s(?:.+?)\s\((?:.+?)jest-resolve\/build\/index\.js/,
     );
   });
 

package.json

@@ -26,6 +26,7 @@
     "ansi-regex": "^5.0.1",
     "ansi-styles": "^5.0.0",
     "babel-jest": "workspace:^",
+    "babel-loader": "^8.2.3",
     "camelcase": "^6.2.0",
     "chalk": "^4.0.0",
     "chokidar": "^3.3.0",
@@ -80,6 +81,8 @@
     "tempy": "^1.0.0",
     "ts-node": "^10.5.0",
     "typescript": "^5.0.4",
+    "webpack": "^5.68.0",
+    "webpack-node-externals": "^3.0.0",
     "which": "^4.0.0"
   },
   "scripts": {

packages/jest-circus/package.json

@@ -15,7 +15,7 @@
       "default": "./build/index.js"
     },
     "./package.json": "./package.json",
-    "./runner": "./runner.js"
+    "./runner": "./build/runner.js"
   },
   "dependencies": {
     "@jest/environment": "workspace:^",

packages/jest-circus/runner.js → packages/jest-circus/src/runner.ts

@@ -6,5 +6,6 @@
  */
 
 // Allow people to use `jest-circus/runner` as a runner.
-const runner = require('./build/legacy-code-todo-rewrite/jestAdapter').default;
-module.exports = runner;
+import runner from './legacy-code-todo-rewrite/jestAdapter';
+
+export default runner;

packages/jest-config/src/normalize.ts

@@ -60,6 +60,9 @@ export type AllOptions = Config.ProjectConfig & Config.GlobalConfig;
 const createConfigError = (message: string) =>
   new ValidationError(ERROR, message, DOCUMENTATION_NOTE);
 
+// we wanna avoid webpack trying to be clever
+const requireResolve = (module: string) => require.resolve(module);
+
 function verifyDirectoryExists(path: string, key: string) {
   try {
     const rootStat = statSync(path);
@@ -525,7 +528,7 @@ export default async function normalize(
   }
 
   options.testEnvironment = resolveTestEnvironment({
-    requireResolveFunction: require.resolve,
+    requireResolveFunction: requireResolve,
     rootDir: options.rootDir,
     testEnvironment:
       options.testEnvironment ||
@@ -667,7 +670,7 @@ export default async function normalize(
             option &&
             resolveRunner(newOptions.resolver, {
               filePath: option,
-              requireResolveFunction: require.resolve,
+              requireResolveFunction: requireResolve,
               rootDir: options.rootDir,
             });
         }
@@ -951,7 +954,7 @@ export default async function normalize(
               config: {},
               path: resolveWatchPlugin(newOptions.resolver, {
                 filePath: watchPlugin,
-                requireResolveFunction: require.resolve,
+                requireResolveFunction: requireResolve,
                 rootDir: options.rootDir,
               }),
             };
@@ -960,7 +963,7 @@ export default async function normalize(
               config: watchPlugin[1] || {},
               path: resolveWatchPlugin(newOptions.resolver, {
                 filePath: watchPlugin[0],
-                requireResolveFunction: require.resolve,
+                requireResolveFunction: requireResolve,
                 rootDir: options.rootDir,
               }),
             };
@@ -995,7 +998,7 @@ export default async function normalize(
   newOptions.testSequencer = resolveSequencer(newOptions.resolver, {
     filePath:
       options.testSequencer || require.resolve(DEFAULT_CONFIG.testSequencer),
-    requireResolveFunction: require.resolve,
+    requireResolveFunction: requireResolve,
     rootDir: options.rootDir,
   });
 

packages/jest-config/src/readConfigFileAndSetRootDir.ts

@@ -112,7 +112,7 @@ function getRegisteredCompiler() {
 async function registerTsNode(): Promise<Service> {
   try {
     // Register TypeScript compiler instance
-    const tsNode = await import('ts-node');
+    const tsNode = await import(/* webpackIgnore: true */ 'ts-node');
     return tsNode.register({
       compilerOptions: {
         module: 'CommonJS',

packages/jest-runner/src/runTest.ts

@@ -98,7 +98,8 @@ async function runTestInternal(
     }
     testEnvironment = resolveTestEnvironment({
       ...projectConfig,
-      requireResolveFunction: require.resolve,
+      // we wanna avoid webpack trying to be clever
+      requireResolveFunction: module => require.resolve(module),
       testEnvironment: customEnvironment,
     });
   }

packages/jest-util/src/requireOrImportModule.ts

@@ -30,7 +30,9 @@ export default async function requireOrImportModule<T>(
         const moduleUrl = pathToFileURL(filePath);
 
         // node `import()` supports URL, but TypeScript doesn't know that
-        const importedModule = await import(moduleUrl.href);
+        const importedModule = await import(
+          /* webpackIgnore: true */ moduleUrl.href
+        );
 
         if (!applyInteropRequireDefault) {
           return importedModule;