All files / lib/internal/modules/esm loader.js

95.8% Statements 502/524
90.8% Branches 79/87
100% Functions 13/13
95.8% Lines 502/524

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 2x 2x 2x 2x 2x 2x 16x 1x 1x 1x 16x 2x 2x 2x 16x 1x 1x 1x 16x 1x 1x 1x 16x 16x 2x 2x 2x 2x 2x 16x 16x 16x 3x 3x 3x 16x 14x 14x 16x 6x 6x 16x 16x 16x 136x 136x 136x 136x 136x 136x 136x 136x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 3x 3x 3x 16x 14x 14x 14x 16x 6x 6x 6x 16x 16x 16x 16x 16x 16x 136x 136x 19x 19x 19x 19x 19x 19x 19x 19x 1x 1x 19x 19x 19x 19x 19x 19x 19x 19x 10x 10x 10x 10x 19x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 1138x 1138x 63x 63x 63x 63x 63x 1138x 1138x 1037x 1037x 1037x 1037x 1129x     1037x 1122x 843x 843x 1037x 1037x 1138x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 843x 843x 843x 801x 801x 801x 837x 2x 2x 799x 799x 843x 843x 843x 843x 124x 843x 843x 843x 843x 843x 843x 843x 843x 843x 843x 843x 843x 843x 843x 843x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 423x 423x 423x 423x 423x 423x 423x 423x 423x 423x 423x 423x 423x 231x 363x 423x 423x 423x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 855x 855x 855x 855x 855x 855x 824x 853x 1x 1x 1x 1x 1x 1x 823x 823x 823x 823x 823x 823x 853x 6x 6x 6x 6x 6x 6x 6x 6x 6x 6x 817x 849x 1x 1x 1x 1x 1x 1x 1x 816x 816x 833x 855x 855x 495x 855x 4x 4x 4x 4x 4x 812x 812x 812x 812x 812x 855x 136x 136x 16x 16x 3x 3x 3x 3x 3x 3x 3x             3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 7x 7x 7x   3x 3x 16x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 1168x 1168x 1168x 1168x 1168x 1168x 11x 1168x 10x 10x 10x 10x 1158x 1158x 1158x 1158x 1158x 1158x 1168x 1168x 1168x 1168x 1168x 1168x 1168x 1168x 1168x 1168x 1168x 1054x 1159x             1054x 1054x 1054x 1054x 1159x 10x 1168x 2x 2x 2x 2x 2x 2x 2x 1159x               1052x 1052x 1052x 1052x 1052x 1168x 136x 136x 136x 136x 136x  
'use strict';
 
// This is needed to avoid cycles in esm/resolve <-> cjs/loader
require('internal/modules/cjs/loader');
 
const {
  Array,
  ArrayIsArray,
  ArrayPrototypeJoin,
  ArrayPrototypePush,
  FunctionPrototypeBind,
  FunctionPrototypeCall,
  ObjectAssign,
  ObjectCreate,
  ObjectSetPrototypeOf,
  PromiseAll,
  RegExpPrototypeExec,
  SafeArrayIterator,
  SafeWeakMap,
  globalThis,
} = primordials;
 
const {
  ERR_INVALID_ARG_TYPE,
  ERR_INVALID_ARG_VALUE,
  ERR_INVALID_MODULE_SPECIFIER,
  ERR_INVALID_RETURN_PROPERTY_VALUE,
  ERR_INVALID_RETURN_VALUE,
  ERR_UNKNOWN_MODULE_FORMAT
} = require('internal/errors').codes;
const { pathToFileURL, isURLInstance } = require('internal/url');
const {
  isAnyArrayBuffer,
  isArrayBufferView,
} = require('internal/util/types');
const ModuleMap = require('internal/modules/esm/module_map');
const ModuleJob = require('internal/modules/esm/module_job');
 
const {
  defaultResolve,
  DEFAULT_CONDITIONS,
} = require('internal/modules/esm/resolve');
const { defaultLoad } = require('internal/modules/esm/load');
const { translators } = require(
  'internal/modules/esm/translators');
const { getOptionValue } = require('internal/options');
 
/**
 * An ESMLoader instance is used as the main entry point for loading ES modules.
 * Currently, this is a singleton -- there is only one used for loading
 * the main module and everything in its dependency graph.
 */
class ESMLoader {
  /**
   * Prior to ESM loading. These are called once before any modules are started.
   * @private
   * @property {function[]} globalPreloaders First-in-first-out list of
   * preload hooks.
   */
  #globalPreloaders = [];
 
  /**
   * Phase 2 of 2 in ESM loading.
   * @private
   * @property {function[]} loaders First-in-first-out list of loader hooks.
   */
  #loaders = [
    defaultLoad,
  ];
 
  /**
   * Phase 1 of 2 in ESM loading.
   * @private
   * @property {function[]} resolvers First-in-first-out list of resolver hooks
   */
  #resolvers = [
    defaultResolve,
  ];
 
  /**
   * Map of already-loaded CJS modules to use
   */
  cjsCache = new SafeWeakMap();
 
  /**
   * The index for assigning unique URLs to anonymous module evaluation
   */
  evalIndex = 0;
 
  /**
   * Registry of loaded modules, akin to `require.cache`
   */
  moduleMap = new ModuleMap();
 
  /**
   * Methods which translate input code or other information into ES modules
   */
  translators = translators;
 
  static pluckHooks({
    globalPreload,
    resolve,
    load,
    // obsolete hooks:
    dynamicInstantiate,
    getFormat,
    getGlobalPreloadCode,
    getSource,
    transformSource,
  }) {
    const obsoleteHooks = [];
    const acceptedHooks = ObjectCreate(null);
 
    if (getGlobalPreloadCode) {
      globalPreload ??= getGlobalPreloadCode;
 
      process.emitWarning(
        'Loader hook "getGlobalPreloadCode" has been renamed to "globalPreload"'
      );
    }
    if (dynamicInstantiate) ArrayPrototypePush(
      obsoleteHooks,
      'dynamicInstantiate'
    );
    if (getFormat) ArrayPrototypePush(
      obsoleteHooks,
      'getFormat',
    );
    if (getSource) ArrayPrototypePush(
      obsoleteHooks,
      'getSource',
    );
    if (transformSource) ArrayPrototypePush(
      obsoleteHooks,
      'transformSource',
    );
 
    if (obsoleteHooks.length) process.emitWarning(
      `Obsolete loader hook(s) supplied and will be ignored: ${
        ArrayPrototypeJoin(obsoleteHooks, ', ')
      }`,
      'DeprecationWarning',
    );
 
    // Use .bind() to avoid giving access to the Loader instance when called.
    if (globalPreload) {
      acceptedHooks.globalPreloader =
        FunctionPrototypeBind(globalPreload, null);
    }
    if (resolve) {
      acceptedHooks.resolver = FunctionPrototypeBind(resolve, null);
    }
    if (load) {
      acceptedHooks.loader = FunctionPrototypeBind(load, null);
    }
 
    return acceptedHooks;
  }
 
  /**
   * Collect custom/user-defined hook(s). After all hooks have been collected,
   * calls global preload hook(s).
   * @param {object | object[]} customLoaders A list of exports from
   * user-defined loaders (as returned by ESMLoader.import()).
   */
  async addCustomLoaders(
    customLoaders = [],
  ) {
    if (!ArrayIsArray(customLoaders)) customLoaders = [customLoaders];
 
    for (let i = 0; i < customLoaders.length; i++) {
      const exports = customLoaders[i];
      const {
        globalPreloader,
        resolver,
        loader,
      } = ESMLoader.pluckHooks(exports);
 
      if (globalPreloader) ArrayPrototypePush(
        this.#globalPreloaders,
        FunctionPrototypeBind(globalPreloader, null), // [1]
      );
      if (resolver) ArrayPrototypePush(
        this.#resolvers,
        FunctionPrototypeBind(resolver, null), // [1]
      );
      if (loader) ArrayPrototypePush(
        this.#loaders,
        FunctionPrototypeBind(loader, null), // [1]
      );
    }
 
    // [1] ensure hook function is not bound to ESMLoader instance
 
    this.preload();
  }
 
  async eval(
    source,
    url = pathToFileURL(`${process.cwd()}/[eval${++this.evalIndex}]`).href
  ) {
    const evalInstance = (url) => {
      const { ModuleWrap, callbackMap } = internalBinding('module_wrap');
      const module = new ModuleWrap(url, undefined, source, 0, 0);
      callbackMap.set(module, {
        importModuleDynamically: (specifier, { url }, importAssertions) => {
          return this.import(specifier, url, importAssertions);
        }
      });
 
      return module;
    };
    const job = new ModuleJob(
      this, url, undefined, evalInstance, false, false);
    this.moduleMap.set(url, undefined, job);
    const { module } = await job.run();
 
    return {
      namespace: module.getNamespace(),
    };
  }
 
  /**
   * Get a (possibly still pending) module job from the cache,
   * or create one and return its Promise.
   * @param {string} specifier The string after `from` in an `import` statement,
   *                           or the first parameter of an `import()`
   *                           expression
   * @param {string | undefined} parentURL The URL of the module importing this
   *                                     one, unless this is the Node.js entry
   *                                     point.
   * @param {Record<string, string>} importAssertions Validations for the
   *                                                  module import.
   * @returns {Promise<ModuleJob>} The (possibly pending) module job
   */
  async getModuleJob(specifier, parentURL, importAssertions) {
    let importAssertionsForResolve;
    if (this.#loaders.length !== 1) {
      // We can skip cloning if there are no user provided loaders because
      // the Node.js default resolve hook does not use import assertions.
      importAssertionsForResolve =
        ObjectAssign(ObjectCreate(null), importAssertions);
    }
    const { format, url } =
      await this.resolve(specifier, parentURL, importAssertionsForResolve);
 
    let job = this.moduleMap.get(url, importAssertions.type);
 
    // CommonJS will set functions for lazy job evaluation.
    if (typeof job === 'function') {
      this.moduleMap.set(url, undefined, job = job());
    }
 
    if (job === undefined) {
      job = this.#createModuleJob(url, importAssertions, parentURL, format);
    }
 
    return job;
  }
 
  /**
   * Create and cache an object representing a loaded module.
   * @param {string} url The absolute URL that was resolved for this module
   * @param {Record<string, string>} importAssertions Validations for the
   *                                                  module import.
   * @param {string} [parentURL] The absolute URL of the module importing this
   *                             one, unless this is the Node.js entry point
   * @param {string} [format] The format hint possibly returned by the
   *                          `resolve` hook
   * @returns {Promise<ModuleJob>} The (possibly pending) module job
   */
  #createModuleJob(url, importAssertions, parentURL, format) {
    const moduleProvider = async (url, isMain) => {
      const { format: finalFormat, source } = await this.load(
        url, { format, importAssertions });
 
      const translator = translators.get(finalFormat);
 
      if (!translator) {
        throw new ERR_UNKNOWN_MODULE_FORMAT(finalFormat);
      }
 
      return FunctionPrototypeCall(translator, this, url, source, isMain);
    };
 
    const inspectBrk = (
      parentURL === undefined &&
      getOptionValue('--inspect-brk')
    );
 
    const job = new ModuleJob(
      this,
      url,
      importAssertions,
      moduleProvider,
      parentURL === undefined,
      inspectBrk
    );
 
    this.moduleMap.set(url, importAssertions.type, job);
 
    return job;
  }
 
  /**
   * This method is usually called indirectly as part of the loading processes.
   * Internally, it is used directly to add loaders. Use directly with caution.
   *
   * This method must NOT be renamed: it functions as a dynamic import on a
   * loader module.
   *
   * @param {string | string[]} specifiers Path(s) to the module.
   * @param {string} parentURL Path of the parent importing the module.
   * @param {Record<string, string>} importAssertions Validations for the
   *                                                  module import.
   * @returns {Promise<object | object[]>} A list of module export(s).
   */
  async import(specifiers, parentURL, importAssertions) {
    const wasArr = ArrayIsArray(specifiers);
    if (!wasArr) specifiers = [specifiers];
 
    const count = specifiers.length;
    const jobs = new Array(count);
 
    for (let i = 0; i < count; i++) {
      jobs[i] = this.getModuleJob(specifiers[i], parentURL, importAssertions)
        .then((job) => job.run())
        .then(({ module }) => module.getNamespace());
    }
 
    const namespaces = await PromiseAll(new SafeArrayIterator(jobs));
 
    return wasArr ?
      namespaces :
      namespaces[0];
  }
 
  /**
   * Provide source that is understood by one of Node's translators.
   *
   * The internals of this WILL change when chaining is implemented,
   * depending on the resolution/consensus from #36954
   * @param {string} url The URL/path of the module to be loaded
   * @param {Object} context Metadata about the module
   * @returns {Object}
   */
  async load(url, context = {}) {
    const defaultLoader = this.#loaders[0];
 
    const loader = this.#loaders.length === 1 ?
      defaultLoader :
      this.#loaders[1];
    const loaded = await loader(url, context, defaultLoader);
 
    if (typeof loaded !== 'object') {
      throw new ERR_INVALID_RETURN_VALUE(
        'object',
        'loader load',
        loaded,
      );
    }
 
    const {
      format,
      source,
    } = loaded;
 
    if (format == null) {
      const dataUrl = RegExpPrototypeExec(
        /^data:([^/]+\/[^;,]+)(?:[^,]*?)(;base64)?,/,
        url,
      );
 
      throw new ERR_INVALID_MODULE_SPECIFIER(
        url,
        dataUrl ? `has an unsupported MIME type "${dataUrl[1]}"` : ''
      );
    }
 
    if (typeof format !== 'string') {
      throw new ERR_INVALID_RETURN_PROPERTY_VALUE(
        'string',
        'loader resolve',
        'format',
        format,
      );
    }
 
    if (
      source != null &&
      typeof source !== 'string' &&
      !isAnyArrayBuffer(source) &&
      !isArrayBufferView(source)
    ) throw ERR_INVALID_RETURN_PROPERTY_VALUE(
      'string, an ArrayBuffer, or a TypedArray',
      'loader load',
      'source',
      source
    );
 
    return {
      format,
      source,
    };
  }
 
  preload() {
    const count = this.#globalPreloaders.length;
    if (!count) return;
 
    for (let i = 0; i < count; i++) {
      const preload = this.#globalPreloaders[i]();
 
      if (preload == null) return;
 
      if (typeof preload !== 'string') {
        throw new ERR_INVALID_RETURN_VALUE(
          'string',
          'loader globalPreloadCode',
          preload,
        );
      }
      const { compileFunction } = require('vm');
      const preloadInit = compileFunction(
        preload,
        ['getBuiltin'],
        {
          filename: '<preload>',
        }
      );
      const { NativeModule } = require('internal/bootstrap/loaders');
 
      FunctionPrototypeCall(preloadInit, globalThis, (builtinName) => {
        if (NativeModule.canBeRequiredByUsers(builtinName)) {
          return require(builtinName);
        }
        throw new ERR_INVALID_ARG_VALUE('builtinName', builtinName);
      });
    }
  }
 
  /**
   * Resolve the location of the module.
   *
   * The internals of this WILL change when chaining is implemented,
   * depending on the resolution/consensus from #36954.
   * @param {string} originalSpecifier The specified URL path of the module to
   *                                   be resolved.
   * @param {string} [parentURL] The URL path of the module's parent.
   * @param {ImportAssertions} [importAssertions] Assertions from the import
   *                                              statement or expression.
   * @returns {{ url: string }}
   */
  async resolve(originalSpecifier, parentURL,
                importAssertions = ObjectCreate(null)) {
    const isMain = parentURL === undefined;
 
    if (
      !isMain &&
      typeof parentURL !== 'string' &&
      !isURLInstance(parentURL)
    ) throw new ERR_INVALID_ARG_TYPE(
      'parentURL',
      ['string', 'URL'],
      parentURL,
    );
 
    const conditions = DEFAULT_CONDITIONS;
 
    const defaultResolver = this.#resolvers[0];
 
    const resolver = this.#resolvers.length === 1 ?
      defaultResolver :
      this.#resolvers[1];
    const resolution = await resolver(
      originalSpecifier,
      {
        conditions,
        importAssertions,
        parentURL,
      },
      defaultResolver,
    );
 
    if (typeof resolution !== 'object') {
      throw new ERR_INVALID_RETURN_VALUE(
        'object',
        'loader resolve',
        resolution,
      );
    }
 
    const { format, url } = resolution;
 
    if (
      format != null &&
      typeof format !== 'string'
    ) {
      throw new ERR_INVALID_RETURN_PROPERTY_VALUE(
        'string',
        'loader resolve',
        'format',
        format,
      );
    }
    if (typeof url !== 'string') {
      throw new ERR_INVALID_RETURN_PROPERTY_VALUE(
        'string',
        'loader resolve',
        'url',
        url,
      );
    }
 
    return {
      format,
      url,
    };
  }
}
 
ObjectSetPrototypeOf(ESMLoader.prototype, null);
 
exports.ESMLoader = ESMLoader;