function cloneMap(map, isDeep, cloneFunc) {
  var array = isDeep ? cloneFunc(mapToArray(map), CLONE_DEEP_FLAG) : mapToArray(map);
  return arrayReduce(array, addMapEntry, new map.constructor());
}
Creates a clone of `map`.

@private
@param {Object} map The map to clone.
@param {Function} cloneFunc The function to clone values.
@param {boolean} [isDeep] Specify a deep clone.
@returns {Object} Returns the cloned map.