设置Object Literal的原型 [英] Setting prototype for Object Literal

问题描述

假设我有以下代码;

var A = {a:10};
var B = {b:20};
B.prototype = A;
alert(B.a);

我对B.a的定义不明确。
我做错了吗？如何设置对象文字的原型？

I am getting undefined for B.a . Am I doing something wrong? How do I set the prototype for object literal ?

我知道如何为Constructor对象做。所以下面的代码是完美的

I know how to do for Constructor object. So the following code works perfect

function A(){this.a=10}
function B(){this.b=20}
B.prototype = new A();
b = new B;
alert(b.a);

我如何为对象文字执行此操作？

How do I do it for object literal ?

推荐答案

对象继承自构造函数的原型属性，而不是自己的属性。构造函数的原型被分配给内部 [[原型]] 属性在某些浏览器中可用作 __ proto __ property。

Objects inherit from their constructor's prototype property, not their own. The constructor's prototype is assigned to the internal [[Prototype]] property that is available in some browsers as the __proto__ property.

所以 b 从 a 继承，你需要在<$ c $上放 a c> b 的继承链，例如

So for b to inherit from a, you need to put a on b's inheritance chain, e.g.

经典原型继承：

var a = {a: 'a'};
function B(){}
B.prototype = a;

var b = new B();
alert(b.a); // a

使用ES5 Object.create：

Using ES5 Object.create:

var a = {a: 'a'};
var b = Object.create(a);

alert(b.a); // a

使用Mozilla __ proto __ ：

Using Mozilla __proto__:

var a = {a: 'a'};
var b = {};
b.__proto__ = a;

alert(b.a); // a

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