什么是setPrototypeOf对新对象的性能影响？

问题描述

MDN提示使用 .setPrototypeOf（）会对代码的未来性能产生不良影响。

The MDN hints that using .setPrototypeOf() will have a bad influence on the future performance of your code.

我还读了一些关于为什么改变对象的[[Prototype]]会降低性能的问题。但是没有一个答案真正解释了在后台发生的事情。所以我想知道这是否也适用于新的对象。

I also read a few Questions about why changing the [[Prototype]] of an object will lower the performance. But none of the answers really explained whats going on in the background. So I wonder if this also applies for new Objects.

特别是我真的喜欢这样的事情：

In particular I really like to do things like this:

var MyPrototype = {
    method1 : function(){...},
    method2 : function(){...},
    ...
};

var newObject = Object.setPrototypeOf({
    property : 1,
    property2 : 'text'
}, MyPrototype);

很遗憾你不能用 Object.create 因为它不接受普通对象文字。

Unfortunately you can't do this with Object.create since it doesn't accept a plain object literal.

我使用 setPrototypeOf 是否也减少了执行JS引擎的性能？

Does my use of setPrototypeOf also decrease the performance of the executing JS engine?

推荐答案

如果你担心（显然你应该......）使用<$的性能影响c $ c> Object.setPrototypeOf（），但是想让你的对象创建语法与你的代码结构类似，试试这个：

If you fear (as apparently you should..) the performance impact of using Object.setPrototypeOf(), but want to keep your object creation syntax similar to how your code is structured, try this:

var MyPrototype = {
    method1 : function(){...},
    method2 : function(){...},
    ...
};

var newObject = Object.assign(Object.create(MyPrototype), {
    property : 1,
    property2 : 'text'
});

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