Method resolve

lib/internal/modules/package_map.js:173–195

* Main resolution method. * Returns the package path and subpath for the specifier, or undefined if * the specifier is not in the parent package's dependencies. * Throws ERR_PACKAGE_MAP_EXTERNAL_FILE if parentPath is not within any * mapped package. * @param {string} specifier * @p

(specifier, parentPath)

   * @returns {{packagePath: string, subpath: string}|undefined}
   */
  resolve(specifier, parentPath) {
    const parentKey = this.#getKeyForPath(parentPath);

    if (parentKey === null) {
      throw new ERR_PACKAGE_MAP_EXTERNAL_FILE(specifier, parentPath, this.#configPath);
    }

    const { packageName, subpath } = parsePackageName(specifier);
    const parentEntry = this.#packages.get(parentKey);

    const targetKey = parentEntry.dependencies.get(packageName);
    if (targetKey === undefined) {
      // Package not in parent's dependencies - let the caller throw the appropriate error
      return undefined;
    }

    const targetEntry = this.#packages.get(targetKey);
    if (!targetEntry) {
      throw new ERR_PACKAGE_MAP_KEY_NOT_FOUND(targetKey, this.#configPath);
    }

    return { packagePath: targetEntry.path, subpath };
  }
}

/**