Javascript中的无限原型继承 [英] Infinite prototypal inheritance in Javascript

问题描述

我正在学习Javascript中的原型继承，并且据我所知，我正在尝试使用它将进程发送到无限递归链接。

I'm learning prototypal inheritance in Javascript, and for my understanding I'm trying to use it to send the process into infinite recursive chaining.

我对原型继承的想法是一个对象（它是一个函数）保存原型链接。该对象的任何实例都指向它。因此，如果我说instance.someproperty它会查看父对象的原型链。

My idea of prototypal inheritance is that an object (which is a function) holds prototype link. Any instance of that object points to it. So if I say instance.someproperty it looks into the prototype chain of the parent object.

假设这样，如果我只是将函数原型列表指向自身，它应该进入当对象试图访问某些属性时无限循环。

Assuming this, If I just point function prototype list to itself, it should go into infinite loop when object tries to access some property.

 var p = function(){};

 p.prototype = p;
 // I also tried p.prototype = new p();

 var q = new p();

 // and now when I say q.something, it should never be able to find it.

我想知道为什么这不起作用我怎么能让它进入无限循环。

I want to know why this doesn't work and how can I make it to go into infinite loop.

推荐答案

使用更常见的风格：

function P(){};
P.prototype = P;

在ECMA-262中，内部原型属性由 [[Prototype]] 表示。

In ECMA-262, the internal prototype property is denoted by [[Prototype]].

为 P.prototype 分配不同的对象不会修改 P 的 [[Prototype]] ，所以它的继承链保持为：

Assigning a different object to P.prototype does not modify P's [[Prototype]], so its inheritance chain remains as:

P : P[[Prototype]] -> Function.prototype -> Object.prototype -> null

鉴于 P 和 P.prototype 两者都指向同一个对象， P 实例的 [[prototype]] 链是：

Given that P and P.prototype both point to the same object, the [[prototype]] chain of an instance of P is:

p : p[[Prototype]] -> P : P[[Prototype]] -> Function.prototype -> Object.prototype -> null

所以没有无限循环。

如果没有分配给 P.prototype ，那么 p 的原型链就是：

Without the assignment to P.prototype, p's prototype chain would have been:

p : p[[Prototype]] -> P.prototype -> Object.prototype -> null

要获得无限循环，可以将对象分配给自己的 __proto __ 属性（访问 [[Prototype]] 的公共方式）在那些支持它的浏览器中，但我不确定这是一个好的想法，Firefox抛出：

To get an endless loop, you can assign an object to its own __proto__ property (the public way to access [[Prototype]]) in those browsers that support it, but I'm not sure that's a good idea, Firefox throws:

"TypeError: cyclic __proto__ value".

这篇关于Javascript中的无限原型继承的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！