Function isConditionalExportsMainSugar

lib/internal/modules/esm/resolve.js:557–578

* Is the given exports object using the shorthand syntax? * @param {import('internal/modules/esm/package_config.js').PackageConfig['exports']} exports * @param {URL} packageJSONUrl The URL of the package.json file. * @param {string | URL | undefined} base The base URL. * @returns {boolean}

(exports, packageJSONUrl, base)

 * @returns {boolean}
 */
function isConditionalExportsMainSugar(exports, packageJSONUrl, base) {
  if (typeof exports === 'string' || ArrayIsArray(exports)) { return true; }
  if (typeof exports !== 'object' || exports === null) { return false; }

  const keys = ObjectGetOwnPropertyNames(exports);
  let isConditionalSugar = false;
  let i = 0;
  for (let j = 0; j < keys.length; j++) {
    const key = keys[j];
    const curIsConditionalSugar = key === '' || key[0] !== '.';
    if (i++ === 0) {
      isConditionalSugar = curIsConditionalSugar;
    } else if (isConditionalSugar !== curIsConditionalSugar) {
      throw new ERR_INVALID_PACKAGE_CONFIG(
        fileURLToPath(packageJSONUrl), base,
        '"exports" cannot contain some keys starting with \'.\' and some not.' +
        ' The exports object must either be an object of package subpath keys' +
        ' or an object of main entry condition name keys only.');
    }
  }
  return isConditionalSugar;
}

/**
 * Resolves the exports of a package.