12345678910111213141516171819202122232425
define(['./_baseTimes', './isArguments', './isArray', './isLength', './isString'], function(baseTimes, isArguments, isArray, isLength, isString) {
  /** Used as a safe reference for `undefined` in pre-ES5 environments. */  var undefined;
  /**   * Creates an array of index keys for `object` values of arrays,   * `arguments` objects, and strings, otherwise `null` is returned.   *   * @private   * @param {Object} object The object to query.   * @returns {Array|null} Returns index keys, else `null`.   */  function indexKeys(object) {    var length = object ? object.length : undefined;    if (isLength(length) &&        (isArray(object) || isString(object) || isArguments(object))) {      return baseTimes(length, String);    }    return null;  }
  return indexKeys;});