Object.seal
- 来自ES5
- 可以封闭指定的对象:只能修改对应的属性值,但是不能删除和添加等操作
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/seal
Object.seal
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/seal