Method module

lib/internal/test_runner/mock/mock.js:632–697

(specifier, options = kEmptyObject)

  }

  module(specifier, options = kEmptyObject) {
    emitExperimentalWarning('Module mocking');
    if (typeof specifier !== 'string') {
      if (!isURL(specifier))
        throw new ERR_INVALID_ARG_TYPE('specifier', ['string', 'URL'], specifier);
      specifier = `${specifier}`;
    }
    validateObject(options, 'options');
    debug('module mock entry, specifier = "%s", options = %o', specifier, options);

    const {
      cache,
      moduleExports,
    } = normalizeModuleMockOptions(options);

    const sharedState = setupSharedModuleState();
    const mockSpecifier = StringPrototypeStartsWith(specifier, 'node:') ?
      StringPrototypeSlice(specifier, 5) : specifier;

    // Get the file that called this function. We need four stack frames:
    // vm context -> getStructuredStack() -> this function -> actual caller.
    const filename = getStructuredStack()[3]?.getFileName();
    // If the caller is already a file URL, use it as is. Otherwise, convert it.
    const hasFileProtocol = StringPrototypeStartsWith(filename, 'file://');
    const caller = hasFileProtocol ? filename : pathToFileURL(filename).href;
    const request = { __proto__: null, specifier: mockSpecifier, attributes: kEmptyObject };
    const { format, url } = sharedState.moduleLoader.resolveSync(caller, request);
    debug('module mock, url = "%s", format = "%s", caller = "%s"', url, format, caller);
    if (format) { // Format is not yet known for ambiguous files when detection is enabled.
      validateOneOf(format, 'format', kSupportedFormats);
    }
    const baseURL = URLParse(url);

    if (!baseURL) {
      throw new ERR_INVALID_ARG_VALUE(
        'specifier', specifier, 'cannot compute URL',
      );
    }

    if (baseURL.searchParams.has(kMockSearchParam)) {
      throw new ERR_INVALID_STATE(
        `Cannot mock '${specifier}'. The module is already mocked.`,
      );
    }

    const fullPath = StringPrototypeStartsWith(url, 'file://') ?
      fileURLToPath(url) : null;
    const ctx = new MockModuleContext({
      __proto__: null,
      baseURL: baseURL.href,
      cache,
      caller,
      format,
      fullPath,
      moduleExports,
      sharedState,
      specifier: mockSpecifier,
    });