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ECMA5.1中Object.seal()和Object.freeze()的区别
1 Object.seal(O)的调用
When the seal function is called, the following steps are taken:
If Type(O) is not Object throw a TypeError exception.
For each named own property name P of O,
Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
If desc.[[Configurable]] is true, set desc.[[Configurable]] to false.
Call the [[DefineOwnProperty]] internal method of O with P, desc, and true as arguments.
Set the [[Extensible]] internal property of O to false.
Return O.
2 Object.freeze(O)的调用
If Type(O) is not Object throw a TypeError exception.
For each named own property name P of O,
Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
If IsDataDescriptor(desc) is true, then
If desc.[[Writable]] is true, set desc.[[Writable]] to false.
If desc.[[Configurable]] is true, set desc.[[Configurable]] to false.
Call the [[DefineOwnProperty]] internal method of O with P, desc, and true as arguments.
Set the [[Extensible]] internal property of O to false.
Return O.
这两个函数的区别在于伪代码标记部分,这下是终于搞定这两个函数的区别了。