node/lib/internal/modules/helpers.js

'use strict';

const {
  ArrayPrototypeForEach,
  ArrayPrototypePush,
  MapPrototypeForEach,
  MapPrototypeGet,
  ObjectDefineProperty,
  ObjectFreeze,
  ObjectKeys,
  ObjectPrototypeHasOwnProperty,
  ReflectApply,
  SafeMap,
  SafeSet,
  StringPrototypeCharCodeAt,
  StringPrototypeIncludes,
  StringPrototypeSlice,
  StringPrototypeStartsWith,
  Symbol,
} = primordials;
const {
  ERR_INVALID_ARG_TYPE,
  ERR_INVALID_RETURN_PROPERTY_VALUE,
  ERR_UNKNOWN_BUILTIN_MODULE,
} = require('internal/errors').codes;
const { BuiltinModule } = require('internal/bootstrap/realm');

const { validateString } = require('internal/validators');
const fs = require('fs'); // Import all of `fs` so that it can be monkey-patched.
const internalFS = require('internal/fs/utils');
const path = require('path');
const { pathToFileURL, fileURLToPath, URL } = require('internal/url');
const assert = require('internal/assert');

const { getOptionValue } = require('internal/options');
const { kEmptyObject, setOwnProperty, getLazy } = require('internal/util');
const { inspect } = require('internal/util/inspect');
const { emitWarningSync } = require('internal/process/warning');
const {
  privateSymbols: {
    module_first_parent_private_symbol: kFirstModuleParent,
  },
} = internalBinding('util');
const lazyTmpdir = getLazy(() => require('os').tmpdir());
const { join } = path;

const internalFsBinding = internalBinding('fs');
const { canParse: URLCanParse } = internalBinding('url');
const modulesBinding = internalBinding('modules');
const {
  enableCompileCache: _enableCompileCache,
  getCompileCacheDir: _getCompileCacheDir,
  compileCacheStatus: _compileCacheStatus,
  flushCompileCache,
} = modulesBinding;

const lazyCJSLoader = getLazy(() => require('internal/modules/cjs/loader'));
let debug = require('internal/util/debuglog').debuglog('module', (fn) => {
  debug = fn;
});

/** @typedef {import('internal/modules/cjs/loader.js').Module} Module */

/**
 * Cache for storing resolved real paths of modules.
 * In order to minimize unnecessary lstat() calls, this cache is a list of known-real paths.
 * Set to an empty Map to reset.
 * @type {Map<string, string>}
 */
const realpathCache = new SafeMap();

// Toggleable loader hooks for VFS support. Overrides that return
// `undefined` fall through to the pinned native implementation.
const nativeLoaderMethods = {
  internalModuleStat: (filename) => internalFsBinding.internalModuleStat(filename),
  readFileSync: (filename, options) => fs.readFileSync(filename, options),
  realpathSync: (requestPath) => fs.realpathSync(requestPath, {
    [internalFS.realpathCacheKey]: realpathCache,
  }),
  legacyMainResolve: (pkgPath, main, base) =>
    internalFsBinding.legacyMainResolve(pkgPath, main, base),
  getFormatOfExtensionlessFile: (filePath) =>
    internalFsBinding.getFormatOfExtensionlessFile(filePath),
  readPackageJSON: (jsonPath, isESM, base, specifier) =>
    modulesBinding.readPackageJSON(jsonPath, isESM, base, specifier),
  getNearestParentPackageJSON: (checkPath) =>
    modulesBinding.getNearestParentPackageJSON(checkPath),
  getRootPackageJSON: (checkPath) =>
    modulesBinding.getRootPackageJSON(checkPath),
  getNearestParentPackageJSONType: (checkPath) =>
    modulesBinding.getNearestParentPackageJSONType(checkPath),
  getPackageScopeConfig: (resolved) =>
    modulesBinding.getPackageScopeConfig(resolved),
  getPackageType: (url) => modulesBinding.getPackageType(url),
  // Synthetic hook with no native counterpart: returns the directory at
  // which upward walks (node_modules lookups) must stop for `path`, or
  // undefined to walk to the file system root.
  getResolutionRoot: () => undefined,
};
const loaderMethodKeys = ObjectKeys(nativeLoaderMethods);
// Overrides use this sentinel when they handled a request but their method's
// meaningful result is `undefined`. A plain `undefined` means fall through to
// the native implementation.
const kLoaderOverrideNoResult = Symbol('kLoaderOverrideNoResult');
const loaderOverrides = new SafeMap();
let hasLoaderOverrides = false;

/**
 * @param {string} key Name of the wrapped method in `nativeLoaderMethods`.
 * @param {Function} originalFn Native fallback pinned at load time.
 * @returns {Function} Wrapper that consults `loaderOverrides` and falls
 *   through to `originalFn` when no override is set or when the
 *   override returns `undefined`.
 */
function wrapLoaderMethod(key, originalFn) {
  return function loaderMethodWrapper(...args) {
    if (hasLoaderOverrides) {
      const override = MapPrototypeGet(loaderOverrides, key);
      if (override !== undefined) {
        const result = ReflectApply(override, undefined, args);
        if (result === kLoaderOverrideNoResult) { return undefined; }
        if (result !== undefined) { return result; }
      }
    }
    return ReflectApply(originalFn, undefined, args);
  };
}

/**
 * Toggleable versions of the loader's fs and package.json methods, keyed
 * like `nativeLoaderMethods`. The module loader calls these instead of the
 * native implementations so that VFS overrides can be consulted first.
 */
const loaderMethods = { __proto__: null };
for (let i = 0; i < loaderMethodKeys.length; i++) {
  const key = loaderMethodKeys[i];
  loaderMethods[key] = wrapLoaderMethod(key, nativeLoaderMethods[key]);
}

/**
 * Set override functions for the module loader's fs and package.json
 * operations. Fields are keyed like `nativeLoaderMethods`; missing or
 * nullish fields disable that hook (fast-path restored).
 * @param {Record<string, Function|undefined>} overrides
 */
function setLoaderOverrides(overrides = kEmptyObject) {
  for (let i = 0; i < loaderMethodKeys.length; i++) {
    const key = loaderMethodKeys[i];
    const override = overrides[key];
    if (override) {
      loaderOverrides.set(key, override);
    } else {
      loaderOverrides.delete(key);
    }
  }
  hasLoaderOverrides = loaderOverrides.size > 0;
}

/**
 * Delete every entry in `cache` whose owned string is under
 * `mountPoint`. `cache` is either a plain object (Module._cache,
 * Module._pathCache) or a SafeMap (statCache, realpathCache,
 * the package.json caches). By default the entry KEY is tested;
 * pass `byValue: true` to test the entry value instead (used for
 * Module._pathCache whose keys are `request\0parent` tokens and
 * whose values are the resolved filenames).
 *
 * Mount points live in the reserved VFS namespace so a prefix scan
 * on strings is exact - real-fs entries never match.
 * @param {object|Map<string, *>} cache
 * @param {string} mountPoint Absolute mount-point path
 * @param {boolean} [byValue] Test the entry value instead of the key
 */
function cleanForVfsPrefix(cache, mountPoint, byValue = false) {
  const prefix = mountPoint + path.sep;
  const owns = (s) =>
    typeof s === 'string' &&
    (s === mountPoint || StringPrototypeStartsWith(s, prefix));
  if (typeof cache.forEach === 'function') {
    MapPrototypeForEach(cache, (v, k) => {
      if (owns(byValue ? v : k)) { cache.delete(k); }
    });
  } else {
    ArrayPrototypeForEach(ObjectKeys(cache), (k) => {
      if (owns(byValue ? cache[k] : k)) { delete cache[k]; }
    });
  }
}

/**
 * Drop realpath-cache entries under an unmounted VFS mount point.
 * Called by internal/vfs/setup.js.
 * @param {string} mountPoint Absolute mount-point path
 */
function purgeRealpathCacheForPrefix(mountPoint) {
  cleanForVfsPrefix(realpathCache, mountPoint);
}

/** Whether the `worker` condition applies, i.e. this is a Web Worker thread. */
let workerCondition = false;

function enableWorkerCondition() {
  workerCondition = true;
}

function hasWorkerCondition() {
  return workerCondition;
}

/** @type {Set<string>} */
let cjsConditions;
/** @type {string[]} */
let cjsConditionsArray;

/**
 * Define the conditions that apply to the CommonJS loader.
 * @returns {void}
 */
function initializeCjsConditions() {
  const userConditions = getOptionValue('--conditions');
  const noAddons = getOptionValue('--no-addons');
  const addonConditions = noAddons ? [] : ['node-addons'];
  // TODO: Use this set when resolving pkg#exports conditions in loader.js.
  cjsConditionsArray = [
    'require',
    'node',
    ...addonConditions,
    ...(workerCondition ? ['worker'] : []),
    ...userConditions,
  ];
  if (getOptionValue('--require-module')) {
    cjsConditionsArray.push('module-sync');
  }
  ObjectFreeze(cjsConditionsArray);
  cjsConditions = new SafeSet(cjsConditionsArray);
}

/**
 * Get the conditions that apply to the CommonJS loader.
 * @returns {Set<string>}
 */
function getCjsConditions() {
  if (cjsConditions === undefined) {
    initializeCjsConditions();
  }
  return cjsConditions;
}

function getCjsConditionsArray() {
  if (cjsConditionsArray === undefined) {
    initializeCjsConditions();
  }
  return cjsConditionsArray;
}

/**
 * Provide one of Node.js' public modules to user code.
 * @param {string} id - The identifier/specifier of the builtin module to load
 * @returns {object|undefined}
 */
function loadBuiltinModule(id) {
  if (!BuiltinModule.canBeRequiredByUsers(id)) {
    return;
  }
  /** @type {import('internal/bootstrap/realm.js').BuiltinModule} */
  const mod = BuiltinModule.map.get(id);
  debug('load built-in module %s', id);
  // compileForPublicLoader() throws if canBeRequiredByUsers is false:
  mod.compileForPublicLoader();
  return mod;
}

let isSEABuiltinWarningNeeded_;
function isSEABuiltinWarningNeeded() {
  if (isSEABuiltinWarningNeeded_ === undefined) {
    const { isExperimentalSeaWarningNeeded, isSea } = internalBinding('sea');
    isSEABuiltinWarningNeeded_ = isSea() && isExperimentalSeaWarningNeeded();
  }
  return isSEABuiltinWarningNeeded_;
}

let warnedAboutBuiltins = false;
/**
 * Helpers to load built-in modules for embedder modules.
 * @param {string} id
 * @returns {import('internal/bootstrap/realm.js').BuiltinModule}
 */
function loadBuiltinModuleForEmbedder(id) {
  const normalized = BuiltinModule.normalizeRequirableId(id);
  if (normalized) {
    const mod = loadBuiltinModule(normalized);
    if (mod) {
      return mod;
    }
  }
  if (isSEABuiltinWarningNeeded() && !warnedAboutBuiltins) {
    emitWarningSync(
      'Currently the require() provided to the main script embedded into ' +
      'single-executable applications only supports loading built-in modules.\n' +
      'To load a module from disk after the single executable application is ' +
      'launched, use require("module").createRequire().\n' +
      'Support for bundled module loading or virtual file systems are under ' +
      'discussions in https://github.com/nodejs/single-executable');
    warnedAboutBuiltins = true;
  }
  throw new ERR_UNKNOWN_BUILTIN_MODULE(id);
}

/** @type {Module} */
let $Module = null;
/**
 * Import the Module class on first use.
 * @returns {object}
 */
function lazyModule() {
  return $Module ??= require('internal/modules/cjs/loader').Module;
}

/**
 * Create the module-scoped `require` function to pass into CommonJS modules.
 * @param {Module} mod - The module to create the `require` function for.
 * @returns {function(string): unknown}
 */
function makeRequireFunction(mod) {
  // lazy due to cycle
  const Module = lazyModule();
  if (mod instanceof Module !== true) {
    throw new ERR_INVALID_ARG_TYPE('mod', 'Module', mod);
  }

  function require(path) {
    return mod.require(path);
  }

  /**
   * The `resolve` method that gets attached to module-scope `require`.
   * @param {string} request
   * @param {Parameters<Module['_resolveFilename']>[3]} options
   * @returns {string}
   */
  function resolve(request, options) {
    validateString(request, 'request');
    const { resolveForCJSWithHooks } = lazyCJSLoader();
    // require.resolve() has different behaviors from the internal resolution used by
    // Module._load:
    // 1. When the request resolves to a non-existent built-in, it throws MODULE_NOT_FOUND
    //   instead of UNKNOWN_BUILTIN_MODULE. This is handled by resolveForCJSWithHooks.
    // 2. If the request is a prefixed built-in, the returned value is also prefixed. This
    //   is handled below.
    const { filename, url } = resolveForCJSWithHooks(
      request, mod, /* isMain */ false, {
        __proto__: null,
        shouldSkipModuleHooks: false,
        requireResolveOptions: options ?? {},
      });
    if (url === request && StringPrototypeStartsWith(request, 'node:')) {
      return url;
    }
    return filename;
  }

  require.resolve = resolve;

  /**
   * The `paths` method that gets attached to module-scope `require`.
   * @param {string} request
   * @returns {object}
   */
  function paths(request) {
    validateString(request, 'request');
    return Module._resolveLookupPaths(request, mod);
  }

  resolve.paths = paths;

  setOwnProperty(require, 'main', process.mainModule);

  // Enable support to add extra extension types.
  require.extensions = Module._extensions;

  require.cache = Module._cache;

  return require;
}

/**
 * Remove byte order marker. This catches EF BB BF (the UTF-8 BOM)
 * because the buffer-to-string conversion in `fs.readFileSync()`
 * translates it to FEFF, the UTF-16 BOM.
 * @param {string} content
 * @returns {string}
 */
function stripBOM(content) {
  if (StringPrototypeCharCodeAt(content) === 0xFEFF) {
    content = StringPrototypeSlice(content, 1);
  }
  return content;
}

/**
 * Add built-in modules to a global or REPL scope object.
 * @param {Record<string, unknown>} object - The object such as `globalThis` to add the built-in modules to.
 * @param {string} dummyModuleName - The label representing the set of built-in modules to add.
 */
function addBuiltinLibsToObject(object, dummyModuleName) {
  // Make built-in modules available directly (loaded lazily).
  const Module = require('internal/modules/cjs/loader').Module;
  const { builtinModules } = Module;

  // To require built-in modules in user-land and ignore modules whose
  // `canBeRequiredByUsers` is false. So we create a dummy module object and not
  // use `require()` directly.
  const dummyModule = new Module(dummyModuleName);

  ArrayPrototypeForEach(builtinModules, (name) => {
    // Neither add underscored modules, nor ones that contain slashes (e.g.,
    // 'fs/promises') or ones that are already defined.
    if (name[0] === '_' ||
        StringPrototypeIncludes(name, '/') ||
        ObjectPrototypeHasOwnProperty(object, name)) {
      return;
    }
    // Goals of this mechanism are:
    // - Lazy loading of built-in modules
    // - Having all built-in modules available as non-enumerable properties
    // - Allowing the user to re-assign these variables as if there were no
    //   pre-existing globals with the same name.

    const setReal = (val) => {
      // Deleting the property before re-assigning it disables the
      // getter/setter mechanism.
      delete object[name];
      object[name] = val;
    };

    ObjectDefineProperty(object, name, {
      __proto__: null,
      get: () => {
        const lib = dummyModule.require(name);

        try {
          // Override the current getter/setter and set up a new
          // non-enumerable property.
          ObjectDefineProperty(object, name, {
            __proto__: null,
            get: () => lib,
            set: setReal,
            configurable: true,
            enumerable: false,
          });
        } catch {
          // If the property is no longer configurable, ignore the error.
        }

        return lib;
      },
      set: setReal,
      configurable: true,
      enumerable: false,
    });
  });
}

/**
 * Normalize the referrer name as a URL.
 * If it's a string containing an absolute path or a URL it's normalized as
 * a URL string.
 * Otherwise it's returned as undefined.
 * @param {string | null | undefined} referrerName
 * @returns {string | undefined}
 */
function normalizeReferrerURL(referrerName) {
  if (referrerName === null || referrerName === undefined) {
    return undefined;
  }

  if (typeof referrerName === 'string') {
    if (path.isAbsolute(referrerName)) {
      return pathToFileURL(referrerName).href;
    }

    if (StringPrototypeStartsWith(referrerName, 'file://') ||
    URLCanParse(referrerName)) {
      return referrerName;
    }

    return undefined;
  }

  assert.fail('Unreachable code reached by ' + inspect(referrerName));
}

/**
 * Coerce a URL string to a filename. This is used by the ESM loader
 * to map ESM URLs to entries in the CJS module cache on a best-effort basis.
 * TODO(joyeecheung): this can be rather expensive, cache the result on the
 * ModuleWrap wherever we can.
 * @param {string|undefined} url URL to convert to filename
 * @returns {string|undefined}
 */
function urlToFilename(url) {
  if (url && StringPrototypeStartsWith(url, 'file://')) {
    let urlObj;
    try {
      urlObj = new URL(url);
    } catch {
      // Not a proper URL, return as-is as the cache key.
      return url;
    }
    try {
      return fileURLToPath(urlObj);
    } catch {
      // This is generally only possible when the URL is provided by a custom loader.
      // Just use the path and ignore whether it's absolute or not as there's no such
      // requirement for CJS cache.
      return urlObj.pathname;
    }
  }
  // Not a file URL, return as-is.
  return url;
}

// Whether we have started executing any user-provided CJS code.
// This is set right before we call the wrapped CJS code (not after,
// in case we are half-way in the execution when internals check this).
// Used for internal assertions.
let _hasStartedUserCJSExecution = false;
// Similar to _hasStartedUserCJSExecution but for ESM. This is set
// right before ESM evaluation in the default ESM loader. We do not
// update this during vm SourceTextModule execution because at that point
// some user code must already have been run to execute code via vm
// there is little value checking whether any user JS code is run anyway.
let _hasStartedUserESMExecution = false;

/**
 * Load a public built-in module. ID may or may not be prefixed by `node:` and
 * will be normalized.
 * @param {string} id ID of the built-in to be loaded.
 * @returns {object|undefined} exports of the built-in. Undefined if the built-in
 *   does not exist.
 */
function getBuiltinModule(id) {
  validateString(id, 'id');
  const normalizedId = BuiltinModule.normalizeRequirableId(id);
  return normalizedId ? require(normalizedId) : undefined;
}

/** @type {import('internal/util/types')} */
let _TYPES = null;
/**
 * Lazily loads and returns the internal/util/types module.
 * @returns {object}
 */
function lazyTypes() {
  if (_TYPES !== null) { return _TYPES; }
  return _TYPES = require('internal/util/types');
}


/**
 * Asserts that the given body is a buffer source (either a string, array buffer, or typed array).
 * Throws an error if the body is not a buffer source.
 * @param {string | ArrayBufferView | ArrayBuffer} body - The body to check.
 * @param {boolean} allowString - Whether or not to allow a string as a valid buffer source.
 * @param {string} hookName - The name of the hook being called.
 * @throws {ERR_INVALID_RETURN_PROPERTY_VALUE} If the body is not a buffer source.
 * @returns {void}
 */
function assertBufferSource(body, allowString, hookName) {
  if (allowString && typeof body === 'string') {
    return;
  }
  const { isArrayBufferView, isAnyArrayBuffer } = lazyTypes();
  if (isArrayBufferView(body) || isAnyArrayBuffer(body)) {
    return;
  }
  throw new ERR_INVALID_RETURN_PROPERTY_VALUE(
    `${allowString ? 'string, ' : ''}array buffer, or typed array`,
    hookName,
    'source',
    body,
  );
}

/**
 * Converts a buffer or buffer-like object to a string.
 * @param {string | ArrayBuffer | ArrayBufferView} body - The buffer or buffer-like object to convert to a string.
 * @returns {string} The resulting string.
 */
function stringify(body) {
  if (typeof body === 'string') { return body; }
  assertBufferSource(body, false, 'load');
  return require('internal/encoding').getUtf8Decoder().decode(body);
}

/**
 * Enable on-disk compiled cache for all user modules being compiled in the current Node.js instance
 * after this method is called.
 * This method accepts either:
 * - A string: path to the cache directory.
 * - An options object `{directory?: string, portable?: boolean, readOnly?: boolean}`:
 *   - `directory`: A string path to the cache directory.
 *   - `portable`: If `portable` is true, the cache directory will be considered relative.
 *     Defaults to `NODE_COMPILE_CACHE_PORTABLE === '1'`.
 *   - `readOnly`: If `readOnly` is true, existing cache entries are used but nothing is
 *     written, and the cache directory is not created. Defaults to
 *     `NODE_COMPILE_CACHE_READONLY === '1'`.
 * If cache directory is undefined, it defaults to the `NODE_COMPILE_CACHE` environment variable.
 * If `NODE_COMPILE_CACHE` isn't set, it defaults to `path.join(os.tmpdir(), 'node-compile-cache')`.
 * @param {string | { directory?: string, portable?: boolean, readOnly?: boolean } | undefined} options
 * @returns {{status: number, message?: string, directory?: string}}
 */
function enableCompileCache(options) {
  let portable;
  let readOnly;
  let directory;

  if (typeof options === 'object' && options !== null) {
    ({ directory, portable, readOnly } = options);
  } else {
    directory = options;
  }
  if (directory === undefined) {
    directory = process.env.NODE_COMPILE_CACHE || join(lazyTmpdir(), 'node-compile-cache');
  }
  if (portable === undefined) {
    portable = process.env.NODE_COMPILE_CACHE_PORTABLE === '1';
  }
  if (readOnly === undefined) {
    readOnly = process.env.NODE_COMPILE_CACHE_READONLY === '1';
  }
  const nativeResult = _enableCompileCache(directory, portable, readOnly);
  const result = { status: nativeResult[0] };
  if (nativeResult[1]) {
    result.message = nativeResult[1];
  }
  if (nativeResult[2]) {
    result.directory = nativeResult[2];
  }
  return result;
}

const compileCacheStatus = { __proto__: null };
for (let i = 0; i < _compileCacheStatus.length; ++i) {
  compileCacheStatus[_compileCacheStatus[i]] = i;
}
ObjectFreeze(compileCacheStatus);
const constants = { __proto__: null, compileCacheStatus };
ObjectFreeze(constants);

/**
 * Get the compile cache directory if on-disk compile cache is enabled.
 * @returns {string|undefined} Path to the module compile cache directory if it is enabled,
 *   or undefined otherwise.
 */
function getCompileCacheDir() {
  return _getCompileCacheDir() || undefined;
}

function getRequireStack(parent) {
  const requireStack = [];
  for (let cursor = parent;
    cursor;
    // TODO(joyeecheung): it makes more sense to use kLastModuleParent here.
    cursor = cursor[kFirstModuleParent]) {
    ArrayPrototypePush(requireStack, cursor.filename || cursor.id);
  }
  return requireStack;
}

// Suffixes tried by legacy CommonJS `main` resolution; indexes match
// the values returned by the `legacyMainResolve` C++ binding.
const legacyMainResolveExtensions = [
  '',
  '.js',
  '.json',
  '.node',
  '/index.js',
  '/index.json',
  '/index.node',
  './index.js',
  './index.json',
  './index.node',
];

const legacyMainResolveExtensionsIndexes = {
  // 0-6: when packageConfig.main is defined
  kResolvedByMain: 0,
  kResolvedByMainJs: 1,
  kResolvedByMainJson: 2,
  kResolvedByMainNode: 3,
  kResolvedByMainIndexJs: 4,
  kResolvedByMainIndexJson: 5,
  kResolvedByMainIndexNode: 6,
  // 7-9: when packageConfig.main is not defined
  kResolvedByPackageAndJs: 7,
  kResolvedByPackageAndJson: 8,
  kResolvedByPackageAndNode: 9,
};

module.exports = {
  addBuiltinLibsToObject,
  assertBufferSource,
  cleanForVfsPrefix,
  purgeRealpathCacheForPrefix,
  constants,
  enableCompileCache,
  enableWorkerCondition,
  flushCompileCache,
  getBuiltinModule,
  getCjsConditions,
  getCjsConditionsArray,
  getCompileCacheDir,
  hasWorkerCondition,
  initializeCjsConditions,
  legacyMainResolveExtensions,
  legacyMainResolveExtensionsIndexes,
  kLoaderOverrideNoResult,
  loaderMethods,
  loadBuiltinModuleForEmbedder,
  loadBuiltinModule,
  makeRequireFunction,
  normalizeReferrerURL,
  setLoaderOverrides,
  stringify,
  stripBOM,
  hasStartedUserCJSExecution() {
    return _hasStartedUserCJSExecution;
  },
  setHasStartedUserCJSExecution() {
    _hasStartedUserCJSExecution = true;
  },
  hasStartedUserESMExecution() {
    return _hasStartedUserESMExecution;
  },
  setHasStartedUserESMExecution() {
    _hasStartedUserESMExecution = true;
  },
  urlToFilename,
  getRequireStack,
};