设置Object.prototype .__ proto__而不仅仅是Object.prototype？ [英] Setting Object.prototype.__proto__ instead of just Object.prototype?

问题描述

我正在查看有关node.js事件模块的这篇文章：

I am looking at this article regarding the node.js events module:

http://www.sitepoint.com/nodejs-events-and-eventemitter/

在其中有这样的代码：

Door.prototype.__proto__ = events.EventEmitter.prototype;

据说将Door对象的原型设置为event.EventEmitter的原型。

Which supposedly sets the prototype of the Door object to the prototype of the event.EventEmitter.

我相信我知道原型之间的区别是什么和 proto
但这段代码完全让我困惑。所以我的问题是代替使用：

I believe I know what is the difference between prototype and proto but this code completely confuses me. So my questions is whether instead of using:

Door.prototype.__proto__ = events.EventEmitter.prototype;

该文章的作者不只是使用这行代码：

The author of the article did not just use this line of code:

Door.prototype= events.EventEmitter.prototype;

推荐答案

此代码

Door.prototype.__proto__ = events.EventEmitter.prototype

使 Door.prototype 继承自 events.EventEmitter.prototype 。

所以原型链就像

doorInstance -> Door.prototype -> events.EventEmitter.prototype

此方法类似于

Door.prototype = Object.create(events.EventEmitter.prototype)

不同之处在于修改[[Prototype]]不会创建新对象，但会对性能产生很大的负面影响。

The difference is that modifying the [[Prototype]] does not create a new object, but it has a great negative impact on performance.

，此代码

Door.prototype = events.EventEmitter.prototype

使门实例直接从 events.EventEmitter.prototype 。

也就是说，您将无法在 Door.prototype 中添加特定方法而不会造成污染 events.EventEmitter.prototype 。

That is, you won't be able to add specific methods in Door.prototype without polluting events.EventEmitter.prototype.

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