Function tryPackageMapResolveCJS

lib/internal/modules/cjs/loader.js:690–717

* Try to resolve using package map (if enabled via --experimental-package-map). * @param {string} request - The bare specifier * @param {Module} parent - The parent module * @param {Set } conditions - Export conditions * @returns {string|undefined}

(request, parent, conditions)

 * @returns {string|undefined}
 */
function tryPackageMapResolveCJS(request, parent, conditions) {
  if (!hasPackageMap()) { return undefined; }

  const parentPath = trySelfParentPath(parent);
  if (!parentPath) { return undefined; }

  const mapped = packageMapResolve(request, parentPath);
  if (mapped === undefined) {
    const requireStack = getRequireStack(parent);
    const message = getRequireStackMessage(request, requireStack);
    // eslint-disable-next-line no-restricted-syntax
    const err = new Error(message);
    setOwnProperty(err, 'code', 'MODULE_NOT_FOUND');
    setOwnProperty(err, 'requireStack', requireStack);
    throw err;
  }

  const { packagePath, subpath } = mapped;

  const packageJSONPath = path.resolve(packagePath, 'package.json');
  const pkg = packageJsonReader.read(packageJSONPath);
  if (pkg.exports !== undefined) {
    return resolveExpansion(subpath, packageJSONPath, pkg, parentPath, conditions);
  }

  // No exports - try standard path resolution within the package
  return Module._findPath(subpath, [packagePath], false, conditions);
}

function resolveExpansion(expansion, pkgJsonPath, pkgData, parentPath, conditions) {
  const pkgPath = path.dirname(pkgJsonPath);