Object.create的用例（null） [英] Use cases for Object.create(null)

问题描述

据我所知，使用 Object.create（null）会创建一个没有 proto 属性的对象（即 Object.getPrototypeOf（myObj）=== null ）但有人可以帮我理解一下这个用例是什么吗？

I understand that using Object.create(null) creates an object which has no proto property (i.e. Object.getPrototypeOf( myObj ) === null) but can someone help me understand what are some of the use cases for this?

换句话说，为什么要创建一个完全为空的对象（即不从 Object.prototype 继承任何方法）？

In other words, why would you want to create an object that is completely empty (i.e. doesn't inherit any methods from Object.prototype)?

推荐答案

在非常罕见的情况下，可能已将某些内容添加到 Object.prototype

In very rare instances where something may have been added to Object.prototype

Object.prototype.bar = 'bar';

使用对象可能更好> Object.create（null）因为它不会继承这个，考虑

It may be better to create an Object with Object.create(null) as it won't inherit this, consider

({}).bar;                // bar
// vs
Object.create(null).bar; // undefined

这意味着您不必担心，例如，如果您使用过 for..in loop

This means you don't have to worry for example if you've used a for..in loop

此外，你可以使它失败 instanceof tests

Furthermore, you can make it so you fail instanceof tests

Object.create(null) instanceof Object; // false

这是因为 instanceof 是基本上是针对RHS测试原型链，并且没有这样的链。

This is because instanceof is basically testing the prototype chain against the RHS, and there is no such chain.

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