1// Copyright JS Foundation and other contributors, http://js.foundation 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15// New objects are extensible. 16var empty = {}; 17assert (Object.isExtensible(empty) === true); 18 19// ...but that can be changed. 20Object.preventExtensions(empty); 21assert(Object.isExtensible(empty) === false); 22 23// Sealed objects are by definition non-extensible. 24var sealed = Object.seal({}); 25assert (Object.isExtensible(sealed) === false); 26 27// Frozen objects are also by definition non-extensible. 28var frozen = Object.freeze({}); 29assert(Object.isExtensible(frozen) === false); 30