fix: simplify transform RegExp (#10207)

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ### Fixes
 
+- `[jest-config]` Simplify transform RegExp ([#10207](https://github.com/facebook/jest/pull/10207))
 - `[jest-fake-timers]` Lazily instantiate mock timers ([#10551](https://github.com/facebook/jest/pull/10551))
 - `[jest-runtime]` `require.main` is no longer `undefined` when using `jest.resetModules` ([#10626](https://github.com/facebook/jest/pull/10626))
 - `[@jest/types]` Add missing values for `timers` ([#10632](https://github.com/facebook/jest/pull/10632))

docs/Configuration.md

@@ -1223,7 +1223,7 @@ If the value is `modern`, [`@sinonjs/fake-timers`](https://github.com/sinonjs/fa
 
 ### `transform` [object\<string, pathToTransformer | [pathToTransformer, object]>]
 
-Default: `{"^.+\\.[jt]sx?$": "babel-jest"}`
+Default: `{"\\.[jt]sx?$": "babel-jest"}`
 
 A map from regular expressions to paths to transformers. A transformer is a module that provides a synchronous function for transforming source files. For example, if you wanted to be able to use a new language feature in your modules or tests that aren't yet supported by node, you might plug in one of many compilers that compile a future version of JavaScript to a current one. Example: see the [examples/typescript](https://github.com/facebook/jest/blob/master/examples/typescript/package.json#L16) example or the [webpack tutorial](Webpack.md).
 
@@ -1238,7 +1238,7 @@ You can pass configuration to a transformer like `{filePattern: ['path-to-transf
 
 _Note: a transformer is only run once per file unless the file has changed. During the development of a transformer it can be useful to run Jest with `--no-cache` to frequently [delete Jest's cache](Troubleshooting.md#caching-issues)._
 
-_Note: when adding additional code transformers, this will overwrite the default config and `babel-jest` is no longer automatically loaded. If you want to use it to compile JavaScript or Typescript, it has to be explicitly defined by adding `{"^.+\\.[jt]sx?$": "babel-jest"}` to the transform property. See [babel-jest plugin](https://github.com/facebook/jest/tree/master/packages/babel-jest#setup)_
+_Note: when adding additional code transformers, this will overwrite the default config and `babel-jest` is no longer automatically loaded. If you want to use it to compile JavaScript or Typescript, it has to be explicitly defined by adding `{"\\.[jt]sx?$": "babel-jest"}` to the transform property. See [babel-jest plugin](https://github.com/facebook/jest/tree/master/packages/babel-jest#setup)_
 
 ### `transformIgnorePatterns` [array\<string>]
 

docs/Webpack.md

@@ -125,8 +125,8 @@ _Note: if you are using babel-jest with additional code preprocessors, you have
 
 ```json
 "transform": {
-  "^.+\\.js$": "babel-jest",
-  "^.+\\.css$": "custom-transformer",
+  "\\.js$": "babel-jest",
+  "\\.css$": "custom-transformer",
   ...
 }
 ```

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

@@ -67,7 +67,7 @@ exports[`--showConfig outputs config info and exits 1`] = `
       "timers": "real",
       "transform": [
         [
-          "^.+\\\\.[jt]sx?$",
+          "\\\\.[jt]sx?$",
           "<<REPLACED_JEST_PACKAGES_DIR>>/babel-jest/build/index.js",
           {}
         ]

e2e/coverage-remapping/package.json

@@ -2,7 +2,7 @@
   "jest": {
     "rootDir": "./",
     "transform": {
-      "^.+\\.(ts|js)$": "<rootDir>/typescriptPreprocessor.js"
+      "\\.(ts|js)$": "<rootDir>/typescriptPreprocessor.js"
     },
     "testEnvironment": "node"
   },

e2e/coverage-transform-instrumented/package.json

@@ -2,7 +2,7 @@
   "jest": {
     "rootDir": "./",
     "transform": {
-      "^.+\\.(js)$": "<rootDir>/preprocessor.js"
+      "\\.(js)$": "<rootDir>/preprocessor.js"
     },
     "testRegex": "/__tests__/.*\\.(js)$",
     "testEnvironment": "node",

e2e/global-setup-custom-transform/package.json

@@ -3,7 +3,7 @@
     "testEnvironment": "node",
     "globalSetup": "<rootDir>/setup.js",
     "transform": {
-      "^.+\\.js$": "<rootDir>/transformer.js"
+      "\\.js$": "<rootDir>/transformer.js"
     }
   }
 }

e2e/node-path/package.json

@@ -2,7 +2,7 @@
   "jest": {
     "testEnvironment": "node",
     "transform": {
-      "^.+\\.jsx?$": "../../packages/babel-jest"
+      "\\.jsx?$": "../../packages/babel-jest"
     }
   }
 }

e2e/package.json

@@ -1,7 +1,7 @@
 {
   "jest": {
     "transform": {
-      "^.+\\.js$": "<rootDir>/../packages/babel-jest"
+      "\\.js$": "<rootDir>/../packages/babel-jest"
     },
     "testEnvironment": "node",
     "testPathIgnorePatterns": [

e2e/snapshot-serializers/package.json

@@ -2,7 +2,7 @@
   "jest": {
     "testEnvironment": "node",
     "transform": {
-      "^.+\\.js$": "<rootDir>/transformer.js"
+      "\\.js$": "<rootDir>/transformer.js"
     },
     "snapshotSerializers": [
       "./plugins/foo",

e2e/stack-trace-source-maps-with-coverage/package.json

@@ -2,7 +2,7 @@
   "jest": {
     "rootDir": "./",
     "transform": {
-      "^.+\\.(ts)$": "<rootDir>/preprocessor.js"
+      "\\.(ts)$": "<rootDir>/preprocessor.js"
     },
     "testEnvironment": "node",
     "testRegex": "fails"

e2e/stack-trace-source-maps/package.json

@@ -2,7 +2,7 @@
   "jest": {
     "rootDir": "./",
     "transform": {
-      "^.+\\.(ts)$": "<rootDir>/preprocessor.js"
+      "\\.(ts)$": "<rootDir>/preprocessor.js"
     },
     "testEnvironment": "node",
     "testRegex": "fails"

e2e/transform-linked-modules/package.json

@@ -7,7 +7,7 @@
       "<rootDir>/ignored/"
     ],
     "transform": {
-      "^.+\\.js$": "<rootDir>/preprocessor.js"
+      "\\.js$": "<rootDir>/preprocessor.js"
     }
   }
 }

e2e/transform/cache/package.json

@@ -4,7 +4,7 @@
   "jest": {
     "testEnvironment": "node",
     "transform": {
-      "^.+\\.js$": "<rootDir>/transformer.js"
+      "\\.js$": "<rootDir>/transformer.js"
     }
   }
 }

e2e/transform/custom-instrumenting-preprocessor/package.json

@@ -1,7 +1,7 @@
 {
   "jest": {
     "transform": {
-      "^.+\\.js$": "<rootDir>/preprocessor.js"
+      "\\.js$": "<rootDir>/preprocessor.js"
     },
     "testEnvironment": "node"
   }

e2e/transform/ecmascript-modules-support/package.json

@@ -12,7 +12,7 @@
       "**/__tests__/**/*.mjs"
     ],
     "transform": {
-      "^.+\\.mjs?$": "../../../packages/babel-jest"
+      "\\.mjs?$": "../../../packages/babel-jest"
     }
   }
 }

e2e/transform/multiple-transformers/package.json

@@ -1,9 +1,9 @@
 {
   "jest": {
     "transform": {
-      "^.+\\.css$": "<rootDir>/cssPreprocessor.js",
-      "^.+\\.js$": "<rootDir>/jsPreprocessor.js",
-      "^.+\\.svg$": "<rootDir>/filePreprocessor.js"
+      "\\.css$": "<rootDir>/cssPreprocessor.js",
+      "\\.js$": "<rootDir>/jsPreprocessor.js",
+      "\\.svg$": "<rootDir>/filePreprocessor.js"
     },
     "testEnvironment": "node"
   },

e2e/typescript-coverage/package.json

@@ -2,7 +2,7 @@
   "jest": {
     "rootDir": "./",
     "transform": {
-      "^.+\\.(ts|js)$": "<rootDir>/typescriptPreprocessor.js"
+      "\\.(ts|js)$": "<rootDir>/typescriptPreprocessor.js"
     },
     "testEnvironment": "node"
   },

e2e/v8-coverage/no-sourcemap/package.json

@@ -4,8 +4,8 @@
   "jest": {
     "testEnvironment": "node",
     "transform": {
-      "^.+\\.[jt]sx?$": "babel-jest",
-      "^.+\\.css$": "<rootDir>/cssTransform.js"
+      "\\.[jt]sx?$": "babel-jest",
+      "\\.css$": "<rootDir>/cssTransform.js"
     }
   }
 }

examples/angular/jest.config.js

@@ -2,9 +2,6 @@ module.exports = {
   moduleFileExtensions: ['ts', 'html', 'js', 'json'],
   setupFilesAfterEnv: ['<rootDir>/setupJest.js'],
   transform: {
-    '^.+\\.[t|j]s$': [
-      'babel-jest',
-      {configFile: require.resolve('./.babelrc')},
-    ],
+    '\\.[tj]s$': ['babel-jest', {configFile: require.resolve('./.babelrc')}],
   },
 };

examples/react-native/jest.config.js

@@ -1,6 +1,6 @@
 module.exports = {
   preset: 'react-native',
   transform: {
-    '^.+\\.(js|ts|tsx)$': require.resolve('react-native/jest/preprocessor.js'),
+    '\\.(js|ts|tsx)$': require.resolve('react-native/jest/preprocessor.js'),
   },
 };

jest.config.js

@@ -63,7 +63,7 @@ module.exports = {
     '/e2e/__tests__/iterator-to-null-test.ts',
   ],
   transform: {
-    '^.+\\.[jt]sx?$': '<rootDir>/packages/babel-jest',
+    '\\.[jt]sx?$': '<rootDir>/packages/babel-jest',
   },
   watchPathIgnorePatterns: ['coverage'],
   watchPlugins: [

packages/babel-jest/README.md

@@ -20,6 +20,6 @@ To explicitly define `babel-jest` as a transformer for your JavaScript code, map
 
 ```json
 "transform": {
-  "^.+\\.[t|j]sx?$": "babel-jest"
+  "\\.[jt]sx?$": "babel-jest"
 },
 ```

packages/jest-config/src/ValidConfig.ts

@@ -119,7 +119,7 @@ const initialOptions: Config.InitialOptions = {
   testURL: 'http://localhost',
   timers: 'real',
   transform: {
-    '^.+\\.js$': '<rootDir>/preprocessor.js',
+    '\\.js$': '<rootDir>/preprocessor.js',
   },
   transformIgnorePatterns: [NODE_MODULES_REGEXP],
   unmockedModulePathPatterns: ['mock'],

packages/jest-config/src/__tests__/normalize.test.js

@@ -14,7 +14,7 @@ import Defaults from '../Defaults';
 
 import {DEFAULT_JS_PATTERN} from '../constants';
 
-const DEFAULT_CSS_PATTERN = '^.+\\.(css)$';
+const DEFAULT_CSS_PATTERN = '\\.(css)$';
 
 jest
   .mock('jest-resolve')
@@ -779,7 +779,7 @@ describe('babel-jest', () => {
   });
 
   it('uses babel-jest if babel-jest is explicitly specified in a custom transform options', () => {
-    const customJSPattern = '^.+\\.js$';
+    const customJSPattern = '\\.js$';
     const {options} = normalize(
       {
         rootDir: '/root',

packages/jest-config/src/constants.ts

@@ -8,7 +8,7 @@
 import * as path from 'path';
 
 export const NODE_MODULES = path.sep + 'node_modules' + path.sep;
-export const DEFAULT_JS_PATTERN = '^.+\\.[jt]sx?$';
+export const DEFAULT_JS_PATTERN = '\\.[jt]sx?$';
 export const DEFAULT_REPORTER_LABEL = 'default';
 export const PACKAGE_JSON = 'package.json';
 export const JEST_CONFIG_BASE_NAME = 'jest.config';

packages/jest-reporters/src/__tests__/generateEmptyCoverage.test.js

@@ -51,7 +51,7 @@ describe('generateEmptyCoverage', () => {
         cacheDirectory: os.tmpdir(),
         cwd: rootDir,
         rootDir,
-        transform: [['^.+\\.js$', require.resolve('babel-jest')]],
+        transform: [['\\.js$', require.resolve('babel-jest')]],
       }),
     );
 
@@ -95,7 +95,7 @@ describe('generateEmptyCoverage', () => {
         cacheDirectory: os.tmpdir(),
         cwd: rootDir,
         rootDir,
-        transform: [['^.+\\.js$', require.resolve('babel-jest')]],
+        transform: [['\\.js$', require.resolve('babel-jest')]],
       }),
     );
 
@@ -124,7 +124,7 @@ describe('generateEmptyCoverage', () => {
         cacheDirectory: os.tmpdir(),
         cwd: rootDir,
         rootDir,
-        transform: [['^.+\\.js$', require.resolve('babel-jest')]],
+        transform: [['\\.js$', require.resolve('babel-jest')]],
       }),
     );
 

packages/jest-runtime/src/__tests__/runtime_internal_module.test.js

@@ -22,7 +22,7 @@ describe('Runtime', () => {
   describe('internalModule', () => {
     it('loads modules and applies transforms', () =>
       createRuntime(__filename, {
-        transform: {'^.+\\.js$': './test_preprocessor'},
+        transform: {'\\.js$': './test_preprocessor'},
       }).then(runtime => {
         const modulePath = path.resolve(
           path.dirname(runtime.__mockRootPath),
@@ -35,7 +35,7 @@ describe('Runtime', () => {
 
     it('loads internal modules without applying transforms', () =>
       createRuntime(__filename, {
-        transform: {'^.+\\.js$': './test_preprocessor'},
+        transform: {'\\.js$': './test_preprocessor'},
       }).then(runtime => {
         const modulePath = path.resolve(
           path.dirname(runtime.__mockRootPath),
@@ -47,7 +47,7 @@ describe('Runtime', () => {
 
     it('loads JSON modules and applies transforms', () =>
       createRuntime(__filename, {
-        transform: {'^.+\\.json$': './test_json_preprocessor'},
+        transform: {'\\.json$': './test_json_preprocessor'},
       }).then(runtime => {
         const modulePath = path.resolve(
           path.dirname(runtime.__mockRootPath),
@@ -59,7 +59,7 @@ describe('Runtime', () => {
 
     it('loads internal JSON modules without applying transforms', () =>
       createRuntime(__filename, {
-        transform: {'^.+\\.json$': './test_json_preprocessor'},
+        transform: {'\\.json$': './test_json_preprocessor'},
       }).then(runtime => {
         const modulePath = path.resolve(
           path.dirname(runtime.__mockRootPath),

packages/jest-transform/src/__tests__/__snapshots__/script_transformer.test.js.snap

@@ -58,7 +58,7 @@ Object {
     "timers": "real",
     "transform": Array [
       Array [
-        "^.+\\\\.js$",
+        "\\\\.js$",
         "test_preprocessor",
       ],
     ],
@@ -231,7 +231,7 @@ exports[`ScriptTransformer uses multiple preprocessors 1`] = `
 const TRANSFORMED = {
   filename: '/fruits/banana.js',
   script: 'module.exports = "banana";',
-  config: '{"automock":false,"cache":true,"cacheDirectory":"/cache/","clearMocks":false,"coveragePathIgnorePatterns":[],"cwd":"/test_root_dir/","detectLeaks":false,"detectOpenHandles":false,"errorOnDeprecated":false,"extraGlobals":[],"forceCoverageMatch":[],"globals":{},"haste":{},"injectGlobals":true,"moduleDirectories":[],"moduleFileExtensions":["js"],"moduleLoader":"/test_module_loader_path","moduleNameMapper":[],"modulePathIgnorePatterns":[],"modulePaths":[],"name":"test","prettierPath":"prettier","resetMocks":false,"resetModules":false,"restoreMocks":false,"rootDir":"/","roots":[],"runner":"jest-runner","setupFiles":[],"setupFilesAfterEnv":[],"skipFilter":false,"skipNodeResolution":false,"slowTestThreshold":5,"snapshotSerializers":[],"testEnvironment":"node","testEnvironmentOptions":{},"testLocationInResults":false,"testMatch":[],"testPathIgnorePatterns":[],"testRegex":["\\\\.test\\\\.js$"],"testRunner":"jest-jasmine2","testURL":"http://localhost","timers":"real","transform":[["^.+\\\\.js$","test_preprocessor"],["^.+\\\\.css$","css-preprocessor"]],"transformIgnorePatterns":["/node_modules/"],"watchPathIgnorePatterns":[]}',
+  config: '{"automock":false,"cache":true,"cacheDirectory":"/cache/","clearMocks":false,"coveragePathIgnorePatterns":[],"cwd":"/test_root_dir/","detectLeaks":false,"detectOpenHandles":false,"errorOnDeprecated":false,"extraGlobals":[],"forceCoverageMatch":[],"globals":{},"haste":{},"injectGlobals":true,"moduleDirectories":[],"moduleFileExtensions":["js"],"moduleLoader":"/test_module_loader_path","moduleNameMapper":[],"modulePathIgnorePatterns":[],"modulePaths":[],"name":"test","prettierPath":"prettier","resetMocks":false,"resetModules":false,"restoreMocks":false,"rootDir":"/","roots":[],"runner":"jest-runner","setupFiles":[],"setupFilesAfterEnv":[],"skipFilter":false,"skipNodeResolution":false,"slowTestThreshold":5,"snapshotSerializers":[],"testEnvironment":"node","testEnvironmentOptions":{},"testLocationInResults":false,"testMatch":[],"testPathIgnorePatterns":[],"testRegex":["\\\\.test\\\\.js$"],"testRunner":"jest-jasmine2","testURL":"http://localhost","timers":"real","transform":[["\\\\.js$","test_preprocessor"],["\\\\.css$","css-preprocessor"]],"transformIgnorePatterns":["/node_modules/"],"watchPathIgnorePatterns":[]}',
 };
 `;
 
@@ -248,7 +248,7 @@ exports[`ScriptTransformer uses the supplied preprocessor 1`] = `
 const TRANSFORMED = {
   filename: '/fruits/banana.js',
   script: 'module.exports = "banana";',
-  config: '{"automock":false,"cache":true,"cacheDirectory":"/cache/","clearMocks":false,"coveragePathIgnorePatterns":[],"cwd":"/test_root_dir/","detectLeaks":false,"detectOpenHandles":false,"errorOnDeprecated":false,"extraGlobals":[],"forceCoverageMatch":[],"globals":{},"haste":{},"injectGlobals":true,"moduleDirectories":[],"moduleFileExtensions":["js"],"moduleLoader":"/test_module_loader_path","moduleNameMapper":[],"modulePathIgnorePatterns":[],"modulePaths":[],"name":"test","prettierPath":"prettier","resetMocks":false,"resetModules":false,"restoreMocks":false,"rootDir":"/","roots":[],"runner":"jest-runner","setupFiles":[],"setupFilesAfterEnv":[],"skipFilter":false,"skipNodeResolution":false,"slowTestThreshold":5,"snapshotSerializers":[],"testEnvironment":"node","testEnvironmentOptions":{},"testLocationInResults":false,"testMatch":[],"testPathIgnorePatterns":[],"testRegex":["\\\\.test\\\\.js$"],"testRunner":"jest-jasmine2","testURL":"http://localhost","timers":"real","transform":[["^.+\\\\.js$","test_preprocessor"]],"transformIgnorePatterns":["/node_modules/"],"watchPathIgnorePatterns":[]}',
+  config: '{"automock":false,"cache":true,"cacheDirectory":"/cache/","clearMocks":false,"coveragePathIgnorePatterns":[],"cwd":"/test_root_dir/","detectLeaks":false,"detectOpenHandles":false,"errorOnDeprecated":false,"extraGlobals":[],"forceCoverageMatch":[],"globals":{},"haste":{},"injectGlobals":true,"moduleDirectories":[],"moduleFileExtensions":["js"],"moduleLoader":"/test_module_loader_path","moduleNameMapper":[],"modulePathIgnorePatterns":[],"modulePaths":[],"name":"test","prettierPath":"prettier","resetMocks":false,"resetModules":false,"restoreMocks":false,"rootDir":"/","roots":[],"runner":"jest-runner","setupFiles":[],"setupFilesAfterEnv":[],"skipFilter":false,"skipNodeResolution":false,"slowTestThreshold":5,"snapshotSerializers":[],"testEnvironment":"node","testEnvironmentOptions":{},"testLocationInResults":false,"testMatch":[],"testPathIgnorePatterns":[],"testRegex":["\\\\.test\\\\.js$"],"testRunner":"jest-jasmine2","testURL":"http://localhost","timers":"real","transform":[["\\\\.js$","test_preprocessor"]],"transformIgnorePatterns":["/node_modules/"],"watchPathIgnorePatterns":[]}',
 };
 `;