define(['../lang/isArray', './toObject'], function(isArray, toObject) {

  /** Used to match property names within property paths. */
  var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\n\\]|\\.)*?\1)\]/,
      reIsPlainProp = /^\w*$/;

  /**
   * Checks if `value` is a property name and not a property path.
   *
   * @private
   * @param {*} value The value to check.
   * @param {Object} [object] The object to query keys on.
   * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
   */
  function isKey(value, object) {
    var type = typeof value;
    if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
      return true;
    }
    if (isArray(value)) {
      return false;
    }
    var result = !reIsDeepProp.test(value);
    return result || (object != null && value in toObject(object));
  }

  return isKey;
});