index.ts

/**
 * 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 {execSync} from 'child_process';
import * as nativeModule from 'module';
import * as path from 'path';
import {URL, fileURLToPath, pathToFileURL} from 'url';
import {
  Script,
  // @ts-expect-error: experimental, not added to the types
  SourceTextModule,
  // @ts-expect-error: experimental, not added to the types
  SyntheticModule,
  Context as VMContext,
  // @ts-expect-error: experimental, not added to the types
  Module as VMModule,
} from 'vm';
import {parse as parseCjs} from 'cjs-module-lexer';
import {CoverageInstrumenter, V8Coverage} from 'collect-v8-coverage';
import * as fs from 'graceful-fs';
import stripBOM = require('strip-bom');
import type {
  Jest,
  JestEnvironment,
  Module,
  ModuleWrapper,
} from '@jest/environment';
import {LegacyFakeTimers, ModernFakeTimers} from '@jest/fake-timers';
import type * as JestGlobals from '@jest/globals';
import type {SourceMapRegistry} from '@jest/source-map';
import type {RuntimeTransformResult, V8CoverageResult} from '@jest/test-result';
import {
  CallerTransformOptions,
  ScriptTransformer,
  ShouldInstrumentOptions,
  TransformResult,
  TransformationOptions,
  handlePotentialSyntaxError,
  shouldInstrument,
} from '@jest/transform';
import type {Config, Global} from '@jest/types';
import type {IModuleMap} from 'jest-haste-map';
import HasteMap from 'jest-haste-map';
import {formatStackTrace, separateMessageFromStack} from 'jest-message-util';
import type {MockFunctionMetadata, ModuleMocker} from 'jest-mock';
import {escapePathForRegex} from 'jest-regex-util';
import Resolver from 'jest-resolve';
import Snapshot = require('jest-snapshot');
import {createDirectory, deepCyclicCopy} from 'jest-util';
import {
  createOutsideJestVmPath,
  decodePossibleOutsideJestVmPath,
  findSiblingsWithFileExtension,
} from './helpers';
import type {Context} from './types';

export type {Context} from './types';

const esmIsAvailable = typeof SourceTextModule === 'function';

interface JestGlobals extends Global.TestFrameworkGlobals {
  expect: typeof JestGlobals.expect;
}

interface JestGlobalsWithJest extends JestGlobals {
  jest: typeof JestGlobals.jest;
}

type HasteMapOptions = {
  console?: Console;
  maxWorkers: number;
  resetCache: boolean;
  watch?: boolean;
  watchman: boolean;
};

interface InternalModuleOptions extends Required<CallerTransformOptions> {
  isInternalModule: boolean;
}

const defaultTransformOptions: InternalModuleOptions = {
  isInternalModule: false,
  supportsDynamicImport: esmIsAvailable,
  supportsExportNamespaceFrom: false,
  supportsStaticESM: false,
  supportsTopLevelAwait: false,
};

type InitialModule = Omit<Module, 'require' | 'parent' | 'paths'>;
type ModuleRegistry = Map<string, InitialModule | Module>;

// These are modules that we know
// * are safe to require from the outside (not stateful, not prone to errors passing in instances from different realms), and
// * take sufficiently long to require to warrant an optimization.
// When required from the outside, they use the worker's require cache and are thus
// only loaded once per worker, not once per test file.
// Use /benchmarks/test-file-overhead to measure the impact.
// Note that this only applies when they are required in an internal context;
// users who require one of these modules in their tests will still get the module from inside the VM.
// Prefer listing a module here only if it is impractical to use the jest-resolve-outside-vm-option where it is required,
// e.g. because there are many require sites spread across the dependency graph.
const INTERNAL_MODULE_REQUIRE_OUTSIDE_OPTIMIZED_MODULES = new Set(['chalk']);
const JEST_RESOLVE_OUTSIDE_VM_OPTION = Symbol.for(
  'jest-resolve-outside-vm-option',
);
type ResolveOptions = Parameters<typeof require.resolve>[1] & {
  [JEST_RESOLVE_OUTSIDE_VM_OPTION]?: true;
};

const testTimeoutSymbol = Symbol.for('TEST_TIMEOUT_SYMBOL');
const retryTimesSymbol = Symbol.for('RETRY_TIMES');

const NODE_MODULES = path.sep + 'node_modules' + path.sep;

const getModuleNameMapper = (config: Config.ProjectConfig) => {
  if (
    Array.isArray(config.moduleNameMapper) &&
    config.moduleNameMapper.length
  ) {
    return config.moduleNameMapper.map(([regex, moduleName]) => ({
      moduleName,
      regex: new RegExp(regex),
    }));
  }
  return null;
};

const unmockRegExpCache = new WeakMap();

const EVAL_RESULT_VARIABLE = 'Object.<anonymous>';

type RunScriptEvalResult = {[EVAL_RESULT_VARIABLE]: ModuleWrapper};

const runtimeSupportsVmModules = typeof SyntheticModule === 'function';

const supportsTopLevelAwait =
  runtimeSupportsVmModules &&
  (() => {
    try {
      // eslint-disable-next-line no-new
      new SourceTextModule('await Promise.resolve()');

      return true;
    } catch {
      return false;
    }
  })();

const supportsNodeColonModulePrefixInRequire = (() => {
  try {
    require('node:fs');

    return true;
  } catch {
    return false;
  }
})();

const supportsNodeColonModulePrefixInImport = (() => {
  const res = execSync(
    `node --eval 'import("node:fs").then(() => console.log(true), () => console.log(false));'`,
  );

  return res.toString().trim() === 'true';
})();

export default class Runtime {
  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: Map<string, boolean>;
  private _fakeTimersImplementation:
    | LegacyFakeTimers<unknown>
    | ModernFakeTimers
    | null;
  private readonly _internalModuleRegistry: ModuleRegistry;
  private _isCurrentlyExecutingManualMock: string | null;
  private _mainModule: Module | null;
  private readonly _mockFactories: Map<string, () => unknown>;
  private readonly _mockMetaDataCache: Map<
    string,
    MockFunctionMetadata<unknown, Array<unknown>>
  >;
  private _mockRegistry: Map<string, any>;
  private _isolatedMockRegistry: Map<string, any> | null;
  private readonly _moduleMocker: ModuleMocker;
  private _isolatedModuleRegistry: ModuleRegistry | null;
  private _moduleRegistry: ModuleRegistry;
  private readonly _esmoduleRegistry: Map<Config.Path, VMModule>;
  private readonly _cjsNamedExports: Map<Config.Path, Set<string>>;
  private readonly _esmModuleLinkingMap: WeakMap<VMModule, Promise<unknown>>;
  private readonly _testPath: Config.Path;
  private readonly _resolver: Resolver;
  private _shouldAutoMock: boolean;
  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 readonly _fileTransformsMutex: Map<string, Promise<void>>;
  private _v8CoverageInstrumenter: CoverageInstrumenter | undefined;
  private _v8CoverageResult: V8Coverage | undefined;
  private readonly _transitiveShouldMock: Map<string, boolean>;
  private _unmockList: RegExp | undefined;
  private readonly _virtualMocks: Map<string, boolean>;
  private _moduleImplementation?: typeof nativeModule.Module;
  private readonly jestObjectCaches: Map<string, Jest>;
  private jestGlobals?: JestGlobals;

  constructor(
    config: Config.ProjectConfig,
    environment: JestEnvironment,
    resolver: Resolver,
    transformer: ScriptTransformer,
    cacheFS: Map<string, string>,
    coverageOptions: ShouldInstrumentOptions,
    testPath: Config.Path,
  ) {
    this._cacheFS = cacheFS;
    this._config = config;
    this._coverageOptions = coverageOptions;
    this._currentlyExecutingModulePath = '';
    this._environment = environment;
    this._explicitShouldMock = new Map();
    this._internalModuleRegistry = new Map();
    this._isCurrentlyExecutingManualMock = null;
    this._mainModule = null;
    this._mockFactories = new Map();
    this._mockRegistry = new Map();
    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();
    this._esmoduleRegistry = new Map();
    this._cjsNamedExports = new Map();
    this._esmModuleLinkingMap = new WeakMap();
    this._testPath = testPath;
    this._resolver = resolver;
    this._scriptTransformer = transformer;
    this._shouldAutoMock = config.automock;
    this._sourceMapRegistry = new Map();
    this._fileTransforms = new Map();
    this._fileTransformsMutex = new Map();
    this._virtualMocks = new Map();
    this.jestObjectCaches = new Map();

    this._mockMetaDataCache = new Map();
    this._shouldMockModuleCache = new Map();
    this._shouldUnmockTransitiveDependenciesCache = new Map();
    this._transitiveShouldMock = new Map();

    this._fakeTimersImplementation =
      config.timers === 'legacy'
        ? this._environment.fakeTimers
        : this._environment.fakeTimersModern;

    this._unmockList = unmockRegExpCache.get(config);
    if (!this._unmockList && config.unmockedModulePathPatterns) {
      this._unmockList = new RegExp(
        config.unmockedModulePathPatterns.join('|'),
      );
      unmockRegExpCache.set(config, this._unmockList);
    }

    if (config.automock) {
      config.setupFiles.forEach(filePath => {
        if (filePath.includes(NODE_MODULES)) {
          const moduleID = this._resolver.getModuleID(
            this._virtualMocks,
            filePath,
          );
          this._transitiveShouldMock.set(moduleID, false);
        }
      });
    }

    this.resetModules();
  }

  static shouldInstrument = shouldInstrument;

  static async createContext(
    config: Config.ProjectConfig,
    options: {
      console?: Console;
      maxWorkers: number;
      watch?: boolean;
      watchman: boolean;
    },
  ): Promise<Context> {
    createDirectory(config.cacheDirectory);
    const instance = Runtime.createHasteMap(config, {
      console: options.console,
      maxWorkers: options.maxWorkers,
      resetCache: !config.cache,
      watch: options.watch,
      watchman: options.watchman,
    });
    const hasteMap = await instance.build();

    return {
      config,
      hasteFS: hasteMap.hasteFS,
      moduleMap: hasteMap.moduleMap,
      resolver: Runtime.createResolver(config, hasteMap.moduleMap),
    };
  }

  static createHasteMap(
    config: Config.ProjectConfig,
    options?: HasteMapOptions,
  ): HasteMap {
    const ignorePatternParts = [
      ...config.modulePathIgnorePatterns,
      ...(options && options.watch ? config.watchPathIgnorePatterns : []),
      config.cacheDirectory.startsWith(config.rootDir + path.sep) &&
        config.cacheDirectory,
    ].filter(Boolean);
    const ignorePattern =
      ignorePatternParts.length > 0
        ? new RegExp(ignorePatternParts.join('|'))
        : undefined;

    return HasteMap.create({
      cacheDirectory: config.cacheDirectory,
      computeSha1: config.haste.computeSha1,
      console: options?.console,
      dependencyExtractor: config.dependencyExtractor,
      enableSymlinks: config.haste.enableSymlinks,
      extensions: [Snapshot.EXTENSION].concat(config.moduleFileExtensions),
      forceNodeFilesystemAPI: config.haste.forceNodeFilesystemAPI,
      hasteImplModulePath: config.haste.hasteImplModulePath,
      hasteMapModulePath: config.haste.hasteMapModulePath,
      ignorePattern,
      maxWorkers: options?.maxWorkers || 1,
      mocksPattern: escapePathForRegex(path.sep + '__mocks__' + path.sep),
      name: config.name,
      platforms: config.haste.platforms || ['ios', 'android'],
      resetCache: options?.resetCache,
      retainAllFiles: false,
      rootDir: config.rootDir,
      roots: config.roots,
      throwOnModuleCollision: config.haste.throwOnModuleCollision,
      useWatchman: options?.watchman,
      watch: options?.watch,
    });
  }

  static createResolver(
    config: Config.ProjectConfig,
    moduleMap: IModuleMap,
  ): Resolver {
    return new Resolver(moduleMap, {
      defaultPlatform: config.haste.defaultPlatform,
      extensions: config.moduleFileExtensions.map(extension => '.' + extension),
      hasCoreModules: true,
      moduleDirectories: config.moduleDirectories,
      moduleNameMapper: getModuleNameMapper(config),
      modulePaths: config.modulePaths,
      platforms: config.haste.platforms,
      resolver: config.resolver,
      rootDir: config.rootDir,
    });
  }

  static async runCLI(): Promise<never> {
    throw new Error('The jest-runtime CLI has been moved into jest-repl');
  }

  static getCLIOptions(): never {
    throw new Error('The jest-runtime CLI has been moved into jest-repl');
  }

  // unstable as it should be replaced by https://github.com/nodejs/modules/issues/393, and we don't want people to use it
  unstable_shouldLoadAsEsm(path: Config.Path): boolean {
    return Resolver.unstable_shouldLoadAsEsm(
      path,
      this._config.extensionsToTreatAsEsm,
    );
  }

  // not async _now_, but transform will be
  private async loadEsmModule(
    modulePath: Config.Path,
    query = '',
  ): Promise<VMModule> {
    const cacheKey = modulePath + query;

    if (this._fileTransformsMutex.has(cacheKey)) {
      await this._fileTransformsMutex.get(cacheKey);
    }

    if (!this._esmoduleRegistry.has(cacheKey)) {
      invariant(
        typeof this._environment.getVmContext === 'function',
        'ES Modules are only supported if your test environment has the `getVmContext` function',
      );

      const context = this._environment.getVmContext();

      invariant(context, 'Test environment has been torn down');

      let transformResolve: () => void;
      let transformReject: (error?: unknown) => void;

      this._fileTransformsMutex.set(
        cacheKey,
        new Promise((resolve, reject) => {
          transformResolve = resolve;
          transformReject = reject;
        }),
      );

      invariant(
        transformResolve! && transformReject!,
        'Promise initialization should be sync - please report this bug to Jest!',
      );

      if (this._resolver.isCoreModule(modulePath)) {
        const core = this._importCoreModule(modulePath, context);
        this._esmoduleRegistry.set(cacheKey, core);

        transformResolve();

        return core;
      }

      const transformedCode = await this.transformFileAsync(modulePath, {
        isInternalModule: false,
        supportsDynamicImport: true,
        supportsExportNamespaceFrom: true,
        supportsStaticESM: true,
        supportsTopLevelAwait,
      });

      try {
        const module = new SourceTextModule(transformedCode, {
          context,
          identifier: modulePath,
          importModuleDynamically: async (
            specifier: string,
            referencingModule: VMModule,
          ) => {
            invariant(
              runtimeSupportsVmModules,
              'You need to run with a version of node that supports ES Modules in the VM API. See https://jestjs.io/docs/ecmascript-modules',
            );
            const module = await this.resolveModule(
              specifier,
              referencingModule.identifier,
              referencingModule.context,
            );

            return this.linkAndEvaluateModule(module);
          },
          initializeImportMeta(meta: ImportMeta) {
            meta.url = pathToFileURL(modulePath).href;
          },
        });

        invariant(
          !this._esmoduleRegistry.has(cacheKey),
          `Module cache already has entry ${cacheKey}. This is a bug in Jest, please report it!`,
        );

        this._esmoduleRegistry.set(cacheKey, module);

        transformResolve();
      } catch (error: unknown) {
        transformReject(error);
        throw error;
      }
    }

    const module = this._esmoduleRegistry.get(cacheKey);

    invariant(
      module,
      'Module cache does not contain module. This is a bug in Jest, please open up an issue',
    );

    return module;
  }

  private resolveModule(
    specifier: string,
    referencingIdentifier: string,
    context: VMContext,
  ) {
    if (specifier === '@jest/globals') {
      const fromCache = this._esmoduleRegistry.get('@jest/globals');

      if (fromCache) {
        return fromCache;
      }
      const globals = this.getGlobalsForEsm(referencingIdentifier, context);
      this._esmoduleRegistry.set('@jest/globals', globals);

      return globals;
    }

    if (specifier.startsWith('file://')) {
      specifier = fileURLToPath(specifier);
    }

    const [path, query] = specifier.split('?');

    const resolved = this._resolveModule(referencingIdentifier, path);

    if (
      this._resolver.isCoreModule(resolved) ||
      this.unstable_shouldLoadAsEsm(resolved)
    ) {
      return this.loadEsmModule(resolved, query);
    }

    return this.loadCjsAsEsm(referencingIdentifier, resolved, context);
  }

  private async linkAndEvaluateModule(module: VMModule) {
    if (module.status === 'unlinked') {
      // since we might attempt to link the same module in parallel, stick the promise in a weak map so every call to
      // this method can await it
      this._esmModuleLinkingMap.set(
        module,
        module.link((specifier: string, referencingModule: VMModule) =>
          this.resolveModule(
            specifier,
            referencingModule.identifier,
            referencingModule.context,
          ),
        ),
      );
    }

    await this._esmModuleLinkingMap.get(module);

    if (module.status === 'linked') {
      await module.evaluate();
    }

    return module;
  }

  async unstable_importModule(
    from: Config.Path,
    moduleName?: string,
  ): Promise<void> {
    invariant(
      runtimeSupportsVmModules,
      'You need to run with a version of node that supports ES Modules in the VM API. See https://jestjs.io/docs/ecmascript-modules',
    );

    const [path, query] = (moduleName ?? '').split('?');

    const modulePath = this._resolveModule(from, path);

    const module = await this.loadEsmModule(modulePath, query);

    return this.linkAndEvaluateModule(module);
  }

  private loadCjsAsEsm(
    from: Config.Path,
    modulePath: Config.Path,
    context: VMContext,
  ) {
    // CJS loaded via `import` should share cache with other CJS: https://github.com/nodejs/modules/issues/503
    const cjs = this.requireModuleOrMock(from, modulePath);

    const parsedExports = this.getExportsOfCjs(modulePath);

    const cjsExports = [...parsedExports].filter(exportName => {
      // we don't wanna respect any exports _named_ default as a named export
      if (exportName === 'default') {
        return false;
      }
      return Object.hasOwnProperty.call(cjs, exportName);
    });

    const module = new SyntheticModule(
      [...cjsExports, 'default'],
      function () {
        cjsExports.forEach(exportName => {
          // @ts-expect-error
          this.setExport(exportName, cjs[exportName]);
        });
        // @ts-expect-error: TS doesn't know what `this` is
        this.setExport('default', cjs);
      },
      {context, identifier: modulePath},
    );

    return evaluateSyntheticModule(module);
  }

  private getExportsOfCjs(modulePath: Config.Path) {
    const cachedNamedExports = this._cjsNamedExports.get(modulePath);

    if (cachedNamedExports) {
      return cachedNamedExports;
    }

    const transformedCode =
      this._fileTransforms.get(modulePath)?.code ?? this.readFile(modulePath);

    const {exports, reexports} = parseCjs(transformedCode);

    const namedExports = new Set(exports);

    reexports.forEach(reexport => {
      const resolved = this._resolveModule(modulePath, reexport);

      const exports = this.getExportsOfCjs(resolved);

      exports.forEach(namedExports.add, namedExports);
    });

    this._cjsNamedExports.set(modulePath, namedExports);

    return namedExports;
  }

  requireModule<T = unknown>(
    from: Config.Path,
    moduleName?: string,
    options?: InternalModuleOptions,
    isRequireActual?: boolean | null,
  ): T {
    const moduleID = this._resolver.getModuleID(
      this._virtualMocks,
      from,
      moduleName,
    );
    let modulePath: string | undefined;

    // Some old tests rely on this mocking behavior. Ideally we'll change this
    // to be more explicit.
    const moduleResource = moduleName && this._resolver.getModule(moduleName);
    const manualMock =
      moduleName && this._resolver.getMockModule(from, moduleName);
    if (
      !options?.isInternalModule &&
      !isRequireActual &&
      !moduleResource &&
      manualMock &&
      manualMock !== this._isCurrentlyExecutingManualMock &&
      this._explicitShouldMock.get(moduleID) !== false
    ) {
      modulePath = manualMock;
    }

    if (moduleName && this._resolver.isCoreModule(moduleName)) {
      return this._requireCoreModule(
        moduleName,
        supportsNodeColonModulePrefixInRequire,
      );
    }

    if (!modulePath) {
      modulePath = this._resolveModule(from, moduleName);
    }

    if (this.unstable_shouldLoadAsEsm(modulePath)) {
      // Node includes more info in the message
      const error = new Error(
        `Must use import to load ES Module: ${modulePath}`,
      );

      // @ts-expect-error: `code` is not defined
      error.code = 'ERR_REQUIRE_ESM';

      throw error;
    }

    let moduleRegistry;

    if (options?.isInternalModule) {
      moduleRegistry = this._internalModuleRegistry;
    } else if (this._isolatedModuleRegistry) {
      moduleRegistry = this._isolatedModuleRegistry;
    } else {
      moduleRegistry = this._moduleRegistry;
    }

    const module = moduleRegistry.get(modulePath);
    if (module) {
      return module.exports;
    }

    // We must register the pre-allocated module object first so that any
    // circular dependencies that may arise while evaluating the module can
    // be satisfied.
    const localModule: InitialModule = {
      children: [],
      exports: {},
      filename: modulePath,
      id: modulePath,
      loaded: false,
      path: path.dirname(modulePath),
    };
    moduleRegistry.set(modulePath, localModule);

    try {
      this._loadModule(
        localModule,
        from,
        moduleName,
        modulePath,
        options,
        moduleRegistry,
      );
    } catch (error: unknown) {
      moduleRegistry.delete(modulePath);
      throw error;
    }

    return localModule.exports;
  }

  requireInternalModule<T = unknown>(from: Config.Path, to?: string): T {
    if (to) {
      const require = (
        nativeModule.createRequire ?? nativeModule.createRequireFromPath
      )(from);
      if (INTERNAL_MODULE_REQUIRE_OUTSIDE_OPTIMIZED_MODULES.has(to)) {
        return require(to);
      }
      const outsideJestVmPath = decodePossibleOutsideJestVmPath(to);
      if (outsideJestVmPath) {
        return require(outsideJestVmPath);
      }
    }

    return this.requireModule<T>(from, to, {
      isInternalModule: true,
      supportsDynamicImport: esmIsAvailable,
      supportsExportNamespaceFrom: false,
      supportsStaticESM: false,
      supportsTopLevelAwait: false,
    });
  }

  requireActual<T = unknown>(from: Config.Path, moduleName: string): T {
    return this.requireModule<T>(from, moduleName, undefined, true);
  }

  requireMock<T = unknown>(from: Config.Path, moduleName: string): T {
    const moduleID = this._resolver.getModuleID(
      this._virtualMocks,
      from,
      moduleName,
    );

    if (
      this._isolatedMockRegistry &&
      this._isolatedMockRegistry.get(moduleID)
    ) {
      return this._isolatedMockRegistry.get(moduleID);
    } else if (this._mockRegistry.get(moduleID)) {
      return this._mockRegistry.get(moduleID);
    }

    const mockRegistry = this._isolatedMockRegistry || this._mockRegistry;

    if (this._mockFactories.has(moduleID)) {
      // has check above makes this ok
      const module = this._mockFactories.get(moduleID)!();
      mockRegistry.set(moduleID, module);
      return module as T;
    }

    const manualMockOrStub = this._resolver.getMockModule(from, moduleName);

    let modulePath =
      this._resolver.getMockModule(from, moduleName) ||
      this._resolveModule(from, moduleName);

    let isManualMock =
      manualMockOrStub &&
      !this._resolver.resolveStubModuleName(from, moduleName);
    if (!isManualMock) {
      // If the actual module file has a __mocks__ dir sitting immediately next
      // to it, look to see if there is a manual mock for this file.
      //
      // subDir1/my_module.js
      // subDir1/__mocks__/my_module.js
      // subDir2/my_module.js
      // subDir2/__mocks__/my_module.js
      //
      // Where some other module does a relative require into each of the
      // respective subDir{1,2} directories and expects a manual mock
      // corresponding to that particular my_module.js file.

      const moduleDir = path.dirname(modulePath);
      const moduleFileName = path.basename(modulePath);
      const potentialManualMock = path.join(
        moduleDir,
        '__mocks__',
        moduleFileName,
      );
      if (fs.existsSync(potentialManualMock)) {
        isManualMock = true;
        modulePath = potentialManualMock;
      }
    }
    if (isManualMock) {
      const localModule: InitialModule = {
        children: [],
        exports: {},
        filename: modulePath,
        id: modulePath,
        loaded: false,
        path: path.dirname(modulePath),
      };

      this._loadModule(
        localModule,
        from,
        moduleName,
        modulePath,
        undefined,
        mockRegistry,
      );

      mockRegistry.set(moduleID, localModule.exports);
    } else {
      // Look for a real module to generate an automock from
      mockRegistry.set(moduleID, this._generateMock(from, moduleName));
    }

    return mockRegistry.get(moduleID);
  }

  private _loadModule(
    localModule: InitialModule,
    from: Config.Path,
    moduleName: string | undefined,
    modulePath: Config.Path,
    options: InternalModuleOptions | undefined,
    moduleRegistry: ModuleRegistry,
  ) {
    if (path.extname(modulePath) === '.json') {
      const text = stripBOM(this.readFile(modulePath));

      const transformedFile = this._scriptTransformer.transformJson(
        modulePath,
        this._getFullTransformationOptions(options),
        text,
      );

      localModule.exports =
        this._environment.global.JSON.parse(transformedFile);
    } else if (path.extname(modulePath) === '.node') {
      localModule.exports = require(modulePath);
    } else {
      // Only include the fromPath if a moduleName is given. Else treat as root.
      const fromPath = moduleName ? from : null;
      this._execModule(localModule, options, moduleRegistry, fromPath);
    }
    localModule.loaded = true;
  }

  private _getFullTransformationOptions(
    options: InternalModuleOptions = defaultTransformOptions,
  ): TransformationOptions {
    return {
      ...options,
      ...this._coverageOptions,
    };
  }

  requireModuleOrMock<T = unknown>(from: Config.Path, moduleName: string): T {
    // this module is unmockable
    if (moduleName === '@jest/globals') {
      // @ts-expect-error: we don't care that it's not assignable to T
      return this.getGlobalsForCjs(from);
    }

    try {
      if (this._shouldMock(from, moduleName)) {
        return this.requireMock<T>(from, moduleName);
      } else {
        return this.requireModule<T>(from, moduleName);
      }
    } catch (e) {
      const moduleNotFound = Resolver.tryCastModuleNotFoundError(e);
      if (moduleNotFound) {
        if (
          moduleNotFound.siblingWithSimilarExtensionFound === null ||
          moduleNotFound.siblingWithSimilarExtensionFound === undefined
        ) {
          moduleNotFound.hint = findSiblingsWithFileExtension(
            this._config.moduleFileExtensions,
            from,
            moduleNotFound.moduleName || moduleName,
          );
          moduleNotFound.siblingWithSimilarExtensionFound = Boolean(
            moduleNotFound.hint,
          );
        }
        moduleNotFound.buildMessage(this._config.rootDir);
        throw moduleNotFound;
      }
      throw e;
    }
  }

  isolateModules(fn: () => void): void {
    if (this._isolatedModuleRegistry || this._isolatedMockRegistry) {
      throw new Error(
        'isolateModules cannot be nested inside another isolateModules.',
      );
    }
    this._isolatedModuleRegistry = new Map();
    this._isolatedMockRegistry = new Map();
    try {
      fn();
    } finally {
      // might be cleared within the callback
      this._isolatedModuleRegistry?.clear();
      this._isolatedMockRegistry?.clear();
      this._isolatedModuleRegistry = null;
      this._isolatedMockRegistry = null;
    }
  }

  resetModules(): void {
    this._isolatedModuleRegistry?.clear();
    this._isolatedMockRegistry?.clear();
    this._isolatedModuleRegistry = null;
    this._isolatedMockRegistry = null;
    this._mockRegistry.clear();
    this._moduleRegistry.clear();
    this._esmoduleRegistry.clear();
    this._cjsNamedExports.clear();

    if (this._environment) {
      if (this._environment.global) {
        const envGlobal = this._environment.global;
        (Object.keys(envGlobal) as Array<keyof typeof globalThis>).forEach(
          key => {
            const globalMock = envGlobal[key];
            if (
              ((typeof globalMock === 'object' && globalMock !== null) ||
                typeof globalMock === 'function') &&
              globalMock._isMockFunction === true
            ) {
              globalMock.mockClear();
            }
          },
        );
      }

      if (this._environment.fakeTimers) {
        this._environment.fakeTimers.clearAllTimers();
      }
    }
  }

  async collectV8Coverage(): Promise<void> {
    this._v8CoverageInstrumenter = new CoverageInstrumenter();

    await this._v8CoverageInstrumenter.startInstrumenting();
  }

  async stopCollectingV8Coverage(): Promise<void> {
    if (!this._v8CoverageInstrumenter) {
      throw new Error('You need to call `collectV8Coverage` first.');
    }
    this._v8CoverageResult =
      await this._v8CoverageInstrumenter.stopInstrumenting();
  }

  getAllCoverageInfoCopy(): JestEnvironment['global']['__coverage__'] {
    return deepCyclicCopy(this._environment.global.__coverage__);
  }

  getAllV8CoverageInfoCopy(): V8CoverageResult {
    if (!this._v8CoverageResult) {
      throw new Error('You need to `stopCollectingV8Coverage` first');
    }

    return this._v8CoverageResult
      .filter(res => res.url.startsWith('file://'))
      .map(res => ({...res, url: fileURLToPath(res.url)}))
      .filter(
        res =>
          // TODO: will this work on windows? It might be better if `shouldInstrument` deals with it anyways
          res.url.startsWith(this._config.rootDir) &&
          this._fileTransforms.has(res.url) &&
          shouldInstrument(res.url, this._coverageOptions, this._config),
      )
      .map(result => {
        const transformedFile = this._fileTransforms.get(result.url);

        return {
          codeTransformResult: transformedFile,
          result,
        };
      });
  }

  getSourceMaps(): SourceMapRegistry {
    return this._sourceMapRegistry;
  }

  setMock(
    from: string,
    moduleName: string,
    mockFactory: () => unknown,
    options?: {virtual?: boolean},
  ): void {
    if (options?.virtual) {
      const mockPath = this._resolver.getModulePath(from, moduleName);

      this._virtualMocks.set(mockPath, true);
    }
    const moduleID = this._resolver.getModuleID(
      this._virtualMocks,
      from,
      moduleName,
    );
    this._explicitShouldMock.set(moduleID, true);
    this._mockFactories.set(moduleID, mockFactory);
  }

  restoreAllMocks(): void {
    this._moduleMocker.restoreAllMocks();
  }

  resetAllMocks(): void {
    this._moduleMocker.resetAllMocks();
  }

  clearAllMocks(): void {
    this._moduleMocker.clearAllMocks();
  }

  teardown(): void {
    this.restoreAllMocks();
    this.resetAllMocks();
    this.resetModules();

    this._internalModuleRegistry.clear();
    this._mainModule = null;
    this._mockFactories.clear();
    this._mockMetaDataCache.clear();
    this._shouldMockModuleCache.clear();
    this._shouldUnmockTransitiveDependenciesCache.clear();
    this._explicitShouldMock.clear();
    this._transitiveShouldMock.clear();
    this._virtualMocks.clear();
    this._cacheFS.clear();
    this._unmockList = undefined;

    this._sourceMapRegistry.clear();

    this._fileTransforms.clear();
    this._fileTransformsMutex.clear();
    this.jestObjectCaches.clear();

    this._v8CoverageResult = [];
    this._v8CoverageInstrumenter = undefined;
    this._moduleImplementation = undefined;
  }

  private _resolveModule(from: Config.Path, to?: string) {
    return to ? this._resolver.resolveModule(from, to) : from;
  }

  private _requireResolve(
    from: Config.Path,
    moduleName?: string,
    options: ResolveOptions = {},
  ) {
    if (moduleName == null) {
      throw new Error(
        'The first argument to require.resolve must be a string. Received null or undefined.',
      );
    }

    const {paths} = options;

    if (paths) {
      for (const p of paths) {
        const absolutePath = path.resolve(from, '..', p);
        const module = this._resolver.resolveModuleFromDirIfExists(
          absolutePath,
          moduleName,
          // required to also resolve files without leading './' directly in the path
          {paths: [absolutePath]},
        );
        if (module) {
          return module;
        }
      }

      throw new Resolver.ModuleNotFoundError(
        `Cannot resolve module '${moduleName}' from paths ['${paths.join(
          "', '",
        )}'] from ${from}`,
      );
    }
    try {
      return this._resolveModule(from, moduleName);
    } catch (err) {
      const module = this._resolver.getMockModule(from, moduleName);

      if (module) {
        return module;
      } else {
        throw err;
      }
    }
  }

  private _requireResolvePaths(from: Config.Path, moduleName?: string) {
    if (moduleName == null) {
      throw new Error(
        'The first argument to require.resolve.paths must be a string. Received null or undefined.',
      );
    }
    if (!moduleName.length) {
      throw new Error(
        'The first argument to require.resolve.paths must not be the empty string.',
      );
    }

    if (moduleName[0] === '.') {
      return [path.resolve(from, '..')];
    }
    if (this._resolver.isCoreModule(moduleName)) {
      return null;
    }
    return this._resolver.getModulePaths(path.resolve(from, '..'));
  }

  private _execModule(
    localModule: InitialModule,
    options: InternalModuleOptions | undefined,
    moduleRegistry: ModuleRegistry,
    from: Config.Path | null,
  ) {
    // If the environment was disposed, prevent this module from being executed.
    if (!this._environment.global) {
      return;
    }

    const module = localModule as Module;

    const filename = module.filename;
    const lastExecutingModulePath = this._currentlyExecutingModulePath;
    this._currentlyExecutingModulePath = filename;
    const origCurrExecutingManualMock = this._isCurrentlyExecutingManualMock;
    this._isCurrentlyExecutingManualMock = filename;

    module.children = [];

    Object.defineProperty(module, 'parent', {
      enumerable: true,
      get() {
        const key = from || '';
        return moduleRegistry.get(key) || null;
      },
    });

    module.paths = this._resolver.getModulePaths(module.path);
    Object.defineProperty(module, 'require', {
      value: this._createRequireImplementation(module, options),
    });

    const transformedCode = this.transformFile(filename, options);

    let compiledFunction: ModuleWrapper | null = null;

    const script = this.createScriptFromCode(transformedCode, filename);

    let runScript: RunScriptEvalResult | null = null;

    const vmContext = this._environment.getVmContext();

    if (vmContext) {
      runScript = script.runInContext(vmContext, {filename});
    }

    if (runScript !== null) {
      compiledFunction = runScript[EVAL_RESULT_VARIABLE];
    }

    if (compiledFunction === null) {
      this._logFormattedReferenceError(
        'You are trying to `import` a file after the Jest environment has been torn down.',
      );
      process.exitCode = 1;
      return;
    }

    const jestObject = this._createJestObjectFor(filename);

    this.jestObjectCaches.set(filename, jestObject);

    const lastArgs: [Jest | undefined, ...Array<Global.Global>] = [
      this._config.injectGlobals ? jestObject : undefined, // jest object
      ...this._config.extraGlobals.map<Global.Global>(globalVariable => {
        if (this._environment.global[globalVariable]) {
          return this._environment.global[globalVariable];
        }

        throw new Error(
          `You have requested '${globalVariable}' as a global variable, but it was not present. Please check your config or your global environment.`,
        );
      }),
    ];

    if (!this._mainModule && filename === this._testPath) {
      this._mainModule = module;
    }

    Object.defineProperty(module, 'main', {
      enumerable: true,
      value: this._mainModule,
    });

    try {
      compiledFunction.call(
        module.exports,
        module, // module object
        module.exports, // module exports
        module.require, // require implementation
        module.path, // __dirname
        module.filename, // __filename
        // @ts-expect-error
        ...lastArgs.filter(notEmpty),
      );
    } catch (error) {
      this.handleExecutionError(error, module);
    }

    this._isCurrentlyExecutingManualMock = origCurrExecutingManualMock;
    this._currentlyExecutingModulePath = lastExecutingModulePath;
  }

  private transformFile(
    filename: string,
    options?: InternalModuleOptions,
  ): string {
    const source = this.readFile(filename);

    if (options?.isInternalModule) {
      return source;
    }

    let transformedFile: TransformResult | undefined =
      this._fileTransforms.get(filename);

    if (transformedFile) {
      return transformedFile.code;
    }

    transformedFile = this._scriptTransformer.transform(
      filename,
      this._getFullTransformationOptions(options),
      source,
    );

    this._fileTransforms.set(filename, {
      ...transformedFile,
      wrapperLength: this.constructModuleWrapperStart().length,
    });

    if (transformedFile.sourceMapPath) {
      this._sourceMapRegistry.set(filename, transformedFile.sourceMapPath);
    }
    return transformedFile.code;
  }

  private async transformFileAsync(
    filename: string,
    options?: InternalModuleOptions,
  ): Promise<string> {
    const source = this.readFile(filename);

    if (options?.isInternalModule) {
      return source;
    }

    let transformedFile: TransformResult | undefined =
      this._fileTransforms.get(filename);

    if (transformedFile) {
      return transformedFile.code;
    }

    transformedFile = await this._scriptTransformer.transformAsync(
      filename,
      this._getFullTransformationOptions(options),
      source,
    );

    this._fileTransforms.set(filename, {
      ...transformedFile,
      wrapperLength: this.constructModuleWrapperStart().length,
    });

    if (transformedFile.sourceMapPath) {
      this._sourceMapRegistry.set(filename, transformedFile.sourceMapPath);
    }
    return transformedFile.code;
  }

  private createScriptFromCode(scriptSource: string, filename: string) {
    try {
      const scriptFilename = this._resolver.isCoreModule(filename)
        ? `jest-nodejs-core-${filename}`
        : filename;
      return new Script(this.wrapCodeInModuleWrapper(scriptSource), {
        displayErrors: true,
        filename: scriptFilename,
        // @ts-expect-error: Experimental ESM API
        importModuleDynamically: async (specifier: string) => {
          invariant(
            runtimeSupportsVmModules,
            'You need to run with a version of node that supports ES Modules in the VM API. See https://jestjs.io/docs/ecmascript-modules',
          );

          const context = this._environment.getVmContext?.();

          invariant(context, 'Test environment has been torn down');

          const module = await this.resolveModule(
            specifier,
            scriptFilename,
            context,
          );

          return this.linkAndEvaluateModule(module);
        },
      });
    } catch (e) {
      throw handlePotentialSyntaxError(e);
    }
  }

  private _requireCoreModule(moduleName: string, supportPrefix: boolean) {
    const moduleWithoutNodePrefix =
      supportPrefix && moduleName.startsWith('node:')
        ? moduleName.slice('node:'.length)
        : moduleName;

    if (moduleWithoutNodePrefix === 'process') {
      return this._environment.global.process;
    }

    if (moduleWithoutNodePrefix === 'module') {
      return this._getMockedNativeModule();
    }

    return require(moduleWithoutNodePrefix);
  }

  private _importCoreModule(moduleName: string, context: VMContext) {
    const required = this._requireCoreModule(
      moduleName,
      supportsNodeColonModulePrefixInImport,
    );

    const module = new SyntheticModule(
      ['default', ...Object.keys(required)],
      function () {
        // @ts-expect-error: TS doesn't know what `this` is
        this.setExport('default', required);
        Object.entries(required).forEach(([key, value]) => {
          // @ts-expect-error: TS doesn't know what `this` is
          this.setExport(key, value);
        });
      },
      // should identifier be `node://${moduleName}`?
      {context, identifier: moduleName},
    );

    return evaluateSyntheticModule(module);
  }

  private _getMockedNativeModule(): typeof nativeModule.Module {
    if (this._moduleImplementation) {
      return this._moduleImplementation;
    }

    const createRequire = (modulePath: string | URL) => {
      const filename =
        typeof modulePath === 'string'
          ? modulePath.startsWith('file:///')
            ? fileURLToPath(new URL(modulePath))
            : modulePath
          : fileURLToPath(modulePath);

      if (!path.isAbsolute(filename)) {
        const error = new TypeError(
          `The argument 'filename' must be a file URL object, file URL string, or absolute path string. Received '${filename}'`,
        );
        // @ts-expect-error
        error.code = 'ERR_INVALID_ARG_TYPE';
        throw error;
      }

      return this._createRequireImplementation({
        children: [],
        exports: {},
        filename,
        id: filename,
        loaded: false,
        path: path.dirname(filename),
      });
    };

    // should we implement the class ourselves?
    class Module extends nativeModule.Module {}

    Object.entries(nativeModule.Module).forEach(([key, value]) => {
      // @ts-expect-error
      Module[key] = value;
    });

    Module.Module = Module;

    if ('createRequire' in nativeModule) {
      Module.createRequire = createRequire;
    }
    if ('createRequireFromPath' in nativeModule) {
      Module.createRequireFromPath = function createRequireFromPath(
        filename: string | URL,
      ) {
        if (typeof filename !== 'string') {
          const error = new TypeError(
            `The argument 'filename' must be string. Received '${filename}'.${
              filename instanceof URL
                ? ' Use createRequire for URL filename.'
                : ''
            }`,
          );
          // @ts-expect-error
          error.code = 'ERR_INVALID_ARG_TYPE';
          throw error;
        }
        return createRequire(filename);
      };
    }
    if ('syncBuiltinESMExports' in nativeModule) {
      Module.syncBuiltinESMExports = function syncBuiltinESMExports() {};
    }

    this._moduleImplementation = Module;

    return Module;
  }

  private _generateMock(from: Config.Path, moduleName: string) {
    const modulePath =
      this._resolver.resolveStubModuleName(from, moduleName) ||
      this._resolveModule(from, moduleName);
    if (!this._mockMetaDataCache.has(modulePath)) {
      // This allows us to handle circular dependencies while generating an
      // automock

      this._mockMetaDataCache.set(
        modulePath,
        this._moduleMocker.getMetadata({}) || {},
      );

      // In order to avoid it being possible for automocking to potentially
      // cause side-effects within the module environment, we need to execute
      // the module in isolation. This could cause issues if the module being
      // mocked has calls into side-effectful APIs on another module.
      const origMockRegistry = this._mockRegistry;
      const origModuleRegistry = this._moduleRegistry;
      this._mockRegistry = new Map();
      this._moduleRegistry = new Map();

      const moduleExports = this.requireModule(from, moduleName);

      // Restore the "real" module/mock registries
      this._mockRegistry = origMockRegistry;
      this._moduleRegistry = origModuleRegistry;

      const mockMetadata = this._moduleMocker.getMetadata(moduleExports);
      if (mockMetadata == null) {
        throw new Error(
          `Failed to get mock metadata: ${modulePath}\n\n` +
            `See: https://jestjs.io/docs/manual-mocks#content`,
        );
      }
      this._mockMetaDataCache.set(modulePath, mockMetadata);
    }
    return this._moduleMocker.generateFromMetadata(
      // added above if missing
      this._mockMetaDataCache.get(modulePath)!,
    );
  }

  private _shouldMock(from: Config.Path, moduleName: string): boolean {
    const explicitShouldMock = this._explicitShouldMock;
    const moduleID = this._resolver.getModuleID(
      this._virtualMocks,
      from,
      moduleName,
    );
    const key = from + path.delimiter + moduleID;

    if (explicitShouldMock.has(moduleID)) {
      // guaranteed by `has` above
      return explicitShouldMock.get(moduleID)!;
    }

    if (
      !this._shouldAutoMock ||
      this._resolver.isCoreModule(moduleName) ||
      this._shouldUnmockTransitiveDependenciesCache.get(key)
    ) {
      return false;
    }

    if (this._shouldMockModuleCache.has(moduleID)) {
      // guaranteed by `has` above
      return this._shouldMockModuleCache.get(moduleID)!;
    }

    let modulePath;
    try {
      modulePath = this._resolveModule(from, moduleName);
    } catch (e) {
      const manualMock = this._resolver.getMockModule(from, moduleName);
      if (manualMock) {
        this._shouldMockModuleCache.set(moduleID, true);
        return true;
      }
      throw e;
    }

    if (this._unmockList && this._unmockList.test(modulePath)) {
      this._shouldMockModuleCache.set(moduleID, false);
      return false;
    }

    // transitive unmocking for package managers that store flat packages (npm3)
    const currentModuleID = this._resolver.getModuleID(
      this._virtualMocks,
      from,
    );
    if (
      this._transitiveShouldMock.get(currentModuleID) === false ||
      (from.includes(NODE_MODULES) &&
        modulePath.includes(NODE_MODULES) &&
        ((this._unmockList && this._unmockList.test(from)) ||
          explicitShouldMock.get(currentModuleID) === false))
    ) {
      this._transitiveShouldMock.set(moduleID, false);
      this._shouldUnmockTransitiveDependenciesCache.set(key, true);
      return false;
    }
    this._shouldMockModuleCache.set(moduleID, true);
    return true;
  }

  private _createRequireImplementation(
    from: InitialModule,
    options?: InternalModuleOptions,
  ): NodeRequire {
    const resolve = (moduleName: string, resolveOptions?: ResolveOptions) => {
      const resolved = this._requireResolve(
        from.filename,
        moduleName,
        resolveOptions,
      );
      if (
        resolveOptions?.[JEST_RESOLVE_OUTSIDE_VM_OPTION] &&
        options?.isInternalModule
      ) {
        return createOutsideJestVmPath(resolved);
      }
      return resolved;
    };
    resolve.paths = (moduleName: string) =>
      this._requireResolvePaths(from.filename, moduleName);

    const moduleRequire = (
      options?.isInternalModule
        ? (moduleName: string) =>
            this.requireInternalModule(from.filename, moduleName)
        : this.requireModuleOrMock.bind(this, from.filename)
    ) as NodeRequire;
    moduleRequire.extensions = Object.create(null);
    moduleRequire.resolve = resolve;
    moduleRequire.cache = (() => {
      // TODO: consider warning somehow that this does nothing. We should support deletions, anyways
      const notPermittedMethod = () => true;
      return new Proxy<typeof moduleRequire['cache']>(Object.create(null), {
        defineProperty: notPermittedMethod,
        deleteProperty: notPermittedMethod,
        get: (_target, key) =>
          typeof key === 'string' ? this._moduleRegistry.get(key) : undefined,
        getOwnPropertyDescriptor() {
          return {
            configurable: true,
            enumerable: true,
          };
        },
        has: (_target, key) =>
          typeof key === 'string' && this._moduleRegistry.has(key),
        ownKeys: () => Array.from(this._moduleRegistry.keys()),
        set: notPermittedMethod,
      });
    })();

    Object.defineProperty(moduleRequire, 'main', {
      enumerable: true,
      value: this._mainModule,
    });

    return moduleRequire;
  }

  private _createJestObjectFor(from: Config.Path): Jest {
    const disableAutomock = () => {
      this._shouldAutoMock = false;
      return jestObject;
    };
    const enableAutomock = () => {
      this._shouldAutoMock = true;
      return jestObject;
    };
    const unmock = (moduleName: string) => {
      const moduleID = this._resolver.getModuleID(
        this._virtualMocks,
        from,
        moduleName,
      );
      this._explicitShouldMock.set(moduleID, false);
      return jestObject;
    };
    const deepUnmock = (moduleName: string) => {
      const moduleID = this._resolver.getModuleID(
        this._virtualMocks,
        from,
        moduleName,
      );
      this._explicitShouldMock.set(moduleID, false);
      this._transitiveShouldMock.set(moduleID, false);
      return jestObject;
    };
    const mock: Jest['mock'] = (moduleName, mockFactory, options) => {
      if (mockFactory !== undefined) {
        return setMockFactory(moduleName, mockFactory, options);
      }

      const moduleID = this._resolver.getModuleID(
        this._virtualMocks,
        from,
        moduleName,
      );
      this._explicitShouldMock.set(moduleID, true);
      return jestObject;
    };
    const setMockFactory = (
      moduleName: string,
      mockFactory: () => unknown,
      options?: {virtual?: boolean},
    ) => {
      this.setMock(from, moduleName, mockFactory, options);
      return jestObject;
    };
    const clearAllMocks = () => {
      this.clearAllMocks();
      return jestObject;
    };
    const resetAllMocks = () => {
      this.resetAllMocks();
      return jestObject;
    };
    const restoreAllMocks = () => {
      this.restoreAllMocks();
      return jestObject;
    };
    const _getFakeTimers = () => {
      if (
        !(this._environment.fakeTimers || this._environment.fakeTimersModern)
      ) {
        this._logFormattedReferenceError(
          'You are trying to access a property or method of the Jest environment after it has been torn down.',
        );
        process.exitCode = 1;
      }

      return this._fakeTimersImplementation!;
    };
    const useFakeTimers: Jest['useFakeTimers'] = (type = 'modern') => {
      if (type === 'legacy') {
        this._fakeTimersImplementation = this._environment.fakeTimers;
      } else {
        this._fakeTimersImplementation = this._environment.fakeTimersModern;
      }
      this._fakeTimersImplementation!.useFakeTimers();
      return jestObject;
    };
    const useRealTimers = () => {
      _getFakeTimers().useRealTimers();
      return jestObject;
    };
    const resetModules = () => {
      this.resetModules();
      return jestObject;
    };
    const isolateModules = (fn: () => void) => {
      this.isolateModules(fn);
      return jestObject;
    };
    const fn = this._moduleMocker.fn.bind(this._moduleMocker);
    const spyOn = this._moduleMocker.spyOn.bind(this._moduleMocker);

    const setTimeout = (timeout: number) => {
      if (this._environment.global.jasmine) {
        this._environment.global.jasmine._DEFAULT_TIMEOUT_INTERVAL = timeout;
      } else {
        // @ts-expect-error: https://github.com/Microsoft/TypeScript/issues/24587
        this._environment.global[testTimeoutSymbol] = timeout;
      }
      return jestObject;
    };

    const retryTimes = (numTestRetries: number) => {
      // @ts-expect-error: https://github.com/Microsoft/TypeScript/issues/24587
      this._environment.global[retryTimesSymbol] = numTestRetries;
      return jestObject;
    };

    const jestObject: Jest = {
      advanceTimersByTime: (msToRun: number) =>
        _getFakeTimers().advanceTimersByTime(msToRun),
      advanceTimersToNextTimer: (steps?: number) =>
        _getFakeTimers().advanceTimersToNextTimer(steps),
      autoMockOff: disableAutomock,
      autoMockOn: enableAutomock,
      clearAllMocks,
      clearAllTimers: () => _getFakeTimers().clearAllTimers(),
      createMockFromModule: (moduleName: string) =>
        this._generateMock(from, moduleName),
      deepUnmock,
      disableAutomock,
      doMock: mock,
      dontMock: unmock,
      enableAutomock,
      fn,
      genMockFromModule: (moduleName: string) =>
        this._generateMock(from, moduleName),
      getRealSystemTime: () => {
        const fakeTimers = _getFakeTimers();

        if (fakeTimers instanceof ModernFakeTimers) {
          return fakeTimers.getRealSystemTime();
        } else {
          throw new TypeError(
            'getRealSystemTime is not available when not using modern timers',
          );
        }
      },
      getTimerCount: () => _getFakeTimers().getTimerCount(),
      isMockFunction: this._moduleMocker.isMockFunction,
      isolateModules,
      mock,
      requireActual: this.requireActual.bind(this, from),
      requireMock: this.requireMock.bind(this, from),
      resetAllMocks,
      resetModules,
      restoreAllMocks,
      retryTimes,
      runAllImmediates: () => {
        const fakeTimers = _getFakeTimers();

        if (fakeTimers instanceof LegacyFakeTimers) {
          fakeTimers.runAllImmediates();
        } else {
          throw new TypeError(
            'runAllImmediates is not available when using modern timers',
          );
        }
      },
      runAllTicks: () => _getFakeTimers().runAllTicks(),
      runAllTimers: () => _getFakeTimers().runAllTimers(),
      runOnlyPendingTimers: () => _getFakeTimers().runOnlyPendingTimers(),
      setMock: (moduleName: string, mock: unknown) =>
        setMockFactory(moduleName, () => mock),
      setSystemTime: (now?: number | Date) => {
        const fakeTimers = _getFakeTimers();

        if (fakeTimers instanceof ModernFakeTimers) {
          fakeTimers.setSystemTime(now);
        } else {
          throw new TypeError(
            'setSystemTime is not available when not using modern timers',
          );
        }
      },
      setTimeout,
      spyOn,
      unmock,
      useFakeTimers,
      useRealTimers,
    };
    return jestObject;
  }

  private _logFormattedReferenceError(errorMessage: string) {
    const originalStack = new ReferenceError(errorMessage)
      .stack!.split('\n')
      // Remove this file from the stack (jest-message-utils will keep one line)
      .filter(line => line.indexOf(__filename) === -1)
      .join('\n');

    const {message, stack} = separateMessageFromStack(originalStack);

    console.error(
      `\n${message}\n` +
        formatStackTrace(stack, this._config, {noStackTrace: false}),
    );
  }

  private wrapCodeInModuleWrapper(content: string) {
    return this.constructModuleWrapperStart() + content + '\n}});';
  }

  private constructModuleWrapperStart() {
    const args = this.constructInjectedModuleParameters();

    return '({"' + EVAL_RESULT_VARIABLE + `":function(${args.join(',')}){`;
  }

  private constructInjectedModuleParameters(): Array<string> {
    return [
      'module',
      'exports',
      'require',
      '__dirname',
      '__filename',
      this._config.injectGlobals ? 'jest' : undefined,
      ...this._config.extraGlobals,
    ].filter(notEmpty);
  }

  private handleExecutionError(e: Error, module: Module): never {
    const moduleNotFoundError = Resolver.tryCastModuleNotFoundError(e);
    if (moduleNotFoundError) {
      if (!moduleNotFoundError.requireStack) {
        moduleNotFoundError.requireStack = [module.filename || module.id];

        for (let cursor = module.parent; cursor; cursor = cursor.parent) {
          moduleNotFoundError.requireStack.push(cursor.filename || cursor.id);
        }

        moduleNotFoundError.buildMessage(this._config.rootDir);
      }
      throw moduleNotFoundError;
    }

    throw e;
  }

  private getGlobalsForCjs(from: Config.Path): JestGlobalsWithJest {
    const jest = this.jestObjectCaches.get(from);

    invariant(jest, 'There should always be a Jest object already');

    return {...this.getGlobalsFromEnvironment(), jest};
  }

  private getGlobalsForEsm(
    from: Config.Path,
    context: VMContext,
  ): Promise<VMModule> {
    let jest = this.jestObjectCaches.get(from);

    if (!jest) {
      jest = this._createJestObjectFor(from);

      this.jestObjectCaches.set(from, jest);
    }

    const globals: JestGlobalsWithJest = {
      ...this.getGlobalsFromEnvironment(),
      jest,
    };

    const module = new SyntheticModule(
      Object.keys(globals),
      function () {
        Object.entries(globals).forEach(([key, value]) => {
          // @ts-expect-error: TS doesn't know what `this` is
          this.setExport(key, value);
        });
      },
      {context, identifier: '@jest/globals'},
    );

    return evaluateSyntheticModule(module);
  }

  private getGlobalsFromEnvironment(): JestGlobals {
    if (this.jestGlobals) {
      return {...this.jestGlobals};
    }

    return {
      afterAll: this._environment.global.afterAll,
      afterEach: this._environment.global.afterEach,
      beforeAll: this._environment.global.beforeAll,
      beforeEach: this._environment.global.beforeEach,
      describe: this._environment.global.describe,
      expect: this._environment.global.expect as any,
      fdescribe: this._environment.global.fdescribe,
      fit: this._environment.global.fit,
      it: this._environment.global.it,
      test: this._environment.global.test,
      xdescribe: this._environment.global.xdescribe,
      xit: this._environment.global.xit,
      xtest: this._environment.global.xtest,
    };
  }

  private readFile(filename: Config.Path): string {
    let source = this._cacheFS.get(filename);

    if (!source) {
      source = fs.readFileSync(filename, 'utf8');

      this._cacheFS.set(filename, source);
    }

    return source;
  }

  setGlobalsForRuntime(globals: JestGlobals): void {
    this.jestGlobals = globals;
  }
}

function invariant(condition: unknown, message?: string): asserts condition {
  if (!condition) {
    throw new Error(message);
  }
}

function notEmpty<T>(value: T | null | undefined): value is T {
  return value !== null && value !== undefined;
}

async function evaluateSyntheticModule(module: SyntheticModule) {
  await module.link(() => {
    throw new Error('This should never happen');
  });

  await module.evaluate();

  return module;
}