chore: use Maps throughout jest-runtime (#10968)

Author: SimenB

CHANGELOG.md

@@ -62,6 +62,7 @@
 - `[jest-resolve]` [**BREAKING**] Migrate to ESM ([#10688](https://github.com/facebook/jest/pull/10688))
 - `[jest-resolve-dependencies]` [**BREAKING**] Migrate to ESM ([#10876](https://github.com/facebook/jest/pull/10876))
 - `[jest-mock]` [**BREAKING**] Migrate to ESM ([#10887](https://github.com/facebook/jest/pull/10887))
+- `[jest-resolve, jest-runtime]` [**BREAKING**] Use `Map`s instead of objects for all cached resources ([#10968](https://github.com/facebook/jest/pull/10968))
 - `[jest-runner]` [**BREAKING**] Migrate to ESM ([#10900](https://github.com/facebook/jest/pull/10900))
 - `[jest-runtime]` [**BREAKING**] Remove deprecated and unnused `getSourceMapInfo` from Runtime ([#9969](https://github.com/facebook/jest/pull/9969))
 - `[jest-util]` No longer checking `enumerable` when adding `process.domain` ([#10862](https://github.com/facebook/jest/pull/10862))

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

@@ -91,7 +91,7 @@ export async function run(
       config,
       environment,
       hasteMap.resolver,
-      undefined,
+      new Map(),
       undefined,
       filePath,
     );

packages/jest-resolve/src/index.ts

@@ -31,9 +31,6 @@ type FindNodeModuleConfig = {
   throwIfNotFound?: boolean;
 };
 
-// TODO: replace with a Map in Jest 27
-type BooleanObject = Record<string, boolean>;
-
 export type ResolveModuleConfig = {
   skipNodeResolution?: boolean;
   paths?: Array<Config.Path>;
@@ -314,7 +311,7 @@ class Resolver {
   }
 
   getModuleID(
-    virtualMocks: BooleanObject,
+    virtualMocks: Map<string, boolean>,
     from: Config.Path,
     _moduleName?: string,
   ): string {
@@ -346,7 +343,7 @@ class Resolver {
   }
 
   private _getAbsolutePath(
-    virtualMocks: BooleanObject,
+    virtualMocks: Map<string, boolean>,
     from: Config.Path,
     moduleName: string,
   ): Config.Path | null {
@@ -368,12 +365,12 @@ class Resolver {
   }
 
   private _getVirtualMockPath(
-    virtualMocks: BooleanObject,
+    virtualMocks: Map<string, boolean>,
     from: Config.Path,
     moduleName: string,
   ): Config.Path {
     const virtualMockPath = this.getModulePath(from, moduleName);
-    return virtualMocks[virtualMockPath]
+    return virtualMocks.get(virtualMockPath)
       ? virtualMockPath
       : moduleName
       ? this.resolveModule(from, moduleName)

packages/jest-runner/src/runTest.ts

@@ -146,7 +146,7 @@ async function runTestInternal(
     ? new LeakDetector(environment)
     : null;
 
-  const cacheFS = {[path]: testSource};
+  const cacheFS = new Map([[path, testSource]]);
   setGlobal(environment.global, 'console', testConsole);
 
   const runtime = new Runtime(
@@ -182,8 +182,7 @@ async function runTestInternal(
     environment: 'node',
     handleUncaughtExceptions: false,
     retrieveSourceMap: source => {
-      const sourceMaps = runtime.getSourceMaps();
-      const sourceMapSource = sourceMaps && sourceMaps[source];
+      const sourceMapSource = runtime.getSourceMaps()?.get(source);
 
       if (sourceMapSource) {
         try {

packages/jest-runtime/src/__mocks__/createRuntime.js

@@ -35,27 +35,14 @@ const setupModuleNameMapper = (config, rootDir) => {
 };
 
 const setupTransform = (config, rootDir) => {
-  if (config && config.transform) {
+  if (config?.transform) {
     const transform = config.transform;
     return Object.keys(transform).map(regex => [
       regex,
       path.resolve(rootDir, transform[regex]),
     ]);
   }
-  return [
-    [
-      '^.+\\.[jt]sx?$',
-      path.resolve(
-        __dirname,
-        '..',
-        '..',
-        '..',
-        'babel-jest',
-        'build',
-        'index.js',
-      ),
-    ],
-  ];
+  return [['^.+\\.[jt]sx?$', require.resolve('babel-jest')]];
 };
 
 module.exports = async function createRuntime(filename, config) {
@@ -67,32 +54,29 @@ module.exports = async function createRuntime(filename, config) {
   const moduleNameMapper = setupModuleNameMapper(config, rootDir);
   const transform = setupTransform(config, rootDir);
 
-  config = makeProjectConfig(
-    {
-      cacheDirectory: getCacheDirectory(),
-      cwd: path.resolve(__dirname, '..', '..', '..', '..'),
-      haste: {
-        hasteImplModulePath: path.resolve(
-          __dirname,
-          '..',
-          '..',
-          '..',
-          'jest-haste-map',
-          'src',
-          '__tests__',
-          'haste_impl.js',
-        ),
-      },
-      moduleDirectories: ['node_modules'],
-      moduleFileExtensions: ['js', 'json', 'jsx', 'ts', 'tsx', 'node'],
-      name: 'Runtime-' + filename.replace(/\W/, '-') + '.tests',
-      rootDir,
-      ...config,
-      moduleNameMapper,
-      transform,
+  config = makeProjectConfig({
+    cacheDirectory: getCacheDirectory(),
+    cwd: path.resolve(__dirname, '..', '..', '..', '..'),
+    haste: {
+      hasteImplModulePath: path.resolve(
+        __dirname,
+        '..',
+        '..',
+        '..',
+        'jest-haste-map',
+        'src',
+        '__tests__',
+        'haste_impl.js',
+      ),
     },
-    {},
-  );
+    moduleDirectories: ['node_modules'],
+    moduleFileExtensions: ['js', 'jsx', 'ts', 'tsx', 'json', 'node'],
+    name: 'Runtime-' + filename.replace(/\W/, '-') + '.tests',
+    rootDir,
+    ...config,
+    moduleNameMapper,
+    transform,
+  });
 
   if (!config.roots.length) {
     config.roots = [config.rootDir];
@@ -110,7 +94,7 @@ module.exports = async function createRuntime(filename, config) {
     config,
     environment,
     Runtime.createResolver(config, hasteMap.moduleMap),
-    undefined,
+    new Map(),
     undefined,
     filename,
   );

packages/jest-runtime/src/__tests__/__snapshots__/runtime_require_module_no_ext.test.js.snap

@@ -6,7 +6,7 @@ exports[`Runtime requireModule with no extension throws error pointing out file
 However, Jest was able to find:
 	'./RegularModuleWithWrongExt.txt'
 
-You might want to include a file extension in your import, or update your 'moduleFileExtensions', which is currently ['js', 'json', 'jsx', 'ts', 'tsx', 'node'].
+You might want to include a file extension in your import, or update your 'moduleFileExtensions', which is currently ['js', 'jsx', 'ts', 'tsx', 'json', 'node'].
 
 See https://jestjs.io/docs/en/configuration#modulefileextensions-arraystring"
 `;

packages/jest-runtime/src/index.ts

@@ -102,18 +102,6 @@ type ResolveOptions = Parameters<typeof require.resolve>[1] & {
   [JEST_RESOLVE_OUTSIDE_VM_OPTION]?: true;
 };
 
-type StringMap = Map<string, string>;
-type BooleanMap = Map<string, boolean>;
-
-const fromEntries: typeof Object.fromEntries =
-  Object.fromEntries ??
-  function fromEntries<T>(iterable: Iterable<[string, T]>) {
-    return [...iterable].reduce<Record<string, T>>((obj, [key, val]) => {
-      obj[key] = val;
-      return obj;
-    }, {});
-  };
-
 const testTimeoutSymbol = Symbol.for('TEST_TIMEOUT_SYMBOL');
 const retryTimesSymbol = Symbol.for('RETRY_TIMES');
 
@@ -154,12 +142,12 @@ const supportsTopLevelAwait =
   })();
 
 export default class Runtime {
-  private readonly _cacheFS: StringMap;
+  private readonly _cacheFS: Map<string, string>;
   private readonly _config: Config.ProjectConfig;
   private readonly _coverageOptions: ShouldInstrumentOptions;
   private _currentlyExecutingModulePath: string;
   private readonly _environment: JestEnvironment;
-  private readonly _explicitShouldMock: BooleanMap;
+  private readonly _explicitShouldMock: Map<string, boolean>;
   private _fakeTimersImplementation:
     | LegacyFakeTimers<unknown>
     | ModernFakeTimers
@@ -181,16 +169,19 @@ export default class Runtime {
   private readonly _testPath: Config.Path | undefined;
   private readonly _resolver: Resolver;
   private _shouldAutoMock: boolean;
-  private readonly _shouldMockModuleCache: BooleanMap;
-  private readonly _shouldUnmockTransitiveDependenciesCache: BooleanMap;
-  private readonly _sourceMapRegistry: StringMap;
+  private readonly _shouldMockModuleCache: Map<string, boolean>;
+  private readonly _shouldUnmockTransitiveDependenciesCache: Map<
+    string,
+    boolean
+  >;
+  private readonly _sourceMapRegistry: Map<string, string>;
   private readonly _scriptTransformer: ScriptTransformer;
   private readonly _fileTransforms: Map<string, RuntimeTransformResult>;
   private _v8CoverageInstrumenter: CoverageInstrumenter | undefined;
   private _v8CoverageResult: V8Coverage | undefined;
-  private readonly _transitiveShouldMock: BooleanMap;
+  private readonly _transitiveShouldMock: Map<string, boolean>;
   private _unmockList: RegExp | undefined;
-  private readonly _virtualMocks: BooleanMap;
+  private readonly _virtualMocks: Map<string, boolean>;
   private _moduleImplementation?: typeof nativeModule.Module;
   private readonly jestObjectCaches: Map<string, Jest>;
   private jestGlobals?: JestGlobals;
@@ -199,12 +190,12 @@ export default class Runtime {
     config: Config.ProjectConfig,
     environment: JestEnvironment,
     resolver: Resolver,
-    cacheFS: Record<string, string> = {},
+    cacheFS: Map<string, string>,
     coverageOptions?: ShouldInstrumentOptions,
     // TODO: Make mandatory in Jest 27
     testPath?: Config.Path,
   ) {
-    this._cacheFS = new Map(Object.entries(cacheFS));
+    this._cacheFS = cacheFS;
     this._config = config;
     this._coverageOptions = coverageOptions || {
       changedFiles: undefined,
@@ -222,8 +213,11 @@ export default class Runtime {
     this._mainModule = null;
     this._mockFactories = new Map();
     this._mockRegistry = new Map();
-    // during setup, this cannot be null (and it's fine to explode if it is)
-    this._moduleMocker = this._environment.moduleMocker!;
+    invariant(
+      this._environment.moduleMocker,
+      '`moduleMocker` must be set on an environment when created',
+    );
+    this._moduleMocker = this._environment.moduleMocker;
     this._isolatedModuleRegistry = null;
     this._isolatedMockRegistry = null;
     this._moduleRegistry = new Map();
@@ -256,10 +250,12 @@ export default class Runtime {
     }
 
     if (config.automock) {
-      const virtualMocks = fromEntries(this._virtualMocks);
       config.setupFiles.forEach(filePath => {
-        if (filePath && filePath.includes(NODE_MODULES)) {
-          const moduleID = this._resolver.getModuleID(virtualMocks, filePath);
+        if (filePath.includes(NODE_MODULES)) {
+          const moduleID = this._resolver.getModuleID(
+            this._virtualMocks,
+            filePath,
+          );
           this._transitiveShouldMock.set(moduleID, false);
         }
       });
@@ -575,7 +571,7 @@ export default class Runtime {
     isRequireActual?: boolean | null,
   ): T {
     const moduleID = this._resolver.getModuleID(
-      fromEntries(this._virtualMocks),
+      this._virtualMocks,
       from,
       moduleName,
     );
@@ -670,7 +666,7 @@ export default class Runtime {
 
   requireMock<T = unknown>(from: Config.Path, moduleName: string): T {
     const moduleID = this._resolver.getModuleID(
-      fromEntries(this._virtualMocks),
+      this._virtualMocks,
       from,
       moduleName,
     );
@@ -922,7 +918,7 @@ export default class Runtime {
   }
 
   getSourceMaps(): SourceMapRegistry {
-    return fromEntries(this._sourceMapRegistry);
+    return this._sourceMapRegistry;
   }
 
   setMock(
@@ -937,7 +933,7 @@ export default class Runtime {
       this._virtualMocks.set(mockPath, true);
     }
     const moduleID = this._resolver.getModuleID(
-      fromEntries(this._virtualMocks),
+      this._virtualMocks,
       from,
       moduleName,
     );
@@ -1365,7 +1361,7 @@ export default class Runtime {
   private _shouldMock(from: Config.Path, moduleName: string): boolean {
     const explicitShouldMock = this._explicitShouldMock;
     const moduleID = this._resolver.getModuleID(
-      fromEntries(this._virtualMocks),
+      this._virtualMocks,
       from,
       moduleName,
     );
@@ -1408,7 +1404,7 @@ export default class Runtime {
 
     // transitive unmocking for package managers that store flat packages (npm3)
     const currentModuleID = this._resolver.getModuleID(
-      fromEntries(this._virtualMocks),
+      this._virtualMocks,
       from,
     );
     if (
@@ -1493,7 +1489,7 @@ export default class Runtime {
     };
     const unmock = (moduleName: string) => {
       const moduleID = this._resolver.getModuleID(
-        fromEntries(this._virtualMocks),
+        this._virtualMocks,
         from,
         moduleName,
       );
@@ -1502,7 +1498,7 @@ export default class Runtime {
     };
     const deepUnmock = (moduleName: string) => {
       const moduleID = this._resolver.getModuleID(
-        fromEntries(this._virtualMocks),
+        this._virtualMocks,
         from,
         moduleName,
       );
@@ -1516,7 +1512,7 @@ export default class Runtime {
       }
 
       const moduleID = this._resolver.getModuleID(
-        fromEntries(this._virtualMocks),
+        this._virtualMocks,
         from,
         moduleName,
       );

packages/jest-source-map/src/__tests__/getCallsite.test.ts

@@ -31,7 +31,7 @@ describe('getCallsite', () => {
       throw new Error('Mock error');
     });
 
-    const site = getCallsite(0, {[__filename]: 'mockedSourceMapFile'});
+    const site = getCallsite(0, new Map([[__filename, 'mockedSourceMapFile']]));
 
     expect(site.getFileName()).toEqual(__filename);
     expect(site.getColumnNumber()).toEqual(expect.any(Number));
@@ -59,7 +59,7 @@ describe('getCallsite', () => {
       }
     };
 
-    const site = getCallsite(0, {[__filename]: 'mockedSourceMapFile'});
+    const site = getCallsite(0, new Map([[__filename, 'mockedSourceMapFile']]));
 
     expect(site.getFileName()).toEqual(__filename);
     expect(site.getColumnNumber()).toEqual(sourceMapColumn);

packages/jest-source-map/src/getCallsite.ts

@@ -52,7 +52,7 @@ export default (
 ): callsites.CallSite => {
   const levelAfterThisCall = level + 1;
   const stack = callsites()[levelAfterThisCall];
-  const sourceMapFileName = sourceMaps && sourceMaps[stack.getFileName() || ''];
+  const sourceMapFileName = sourceMaps?.get(stack.getFileName() || '');
 
   if (sourceMapFileName) {
     try {

packages/jest-source-map/src/types.ts

@@ -5,4 +5,4 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-export type SourceMapRegistry = Record<string, string>;
+export type SourceMapRegistry = Map<string, string>;