问题描述
我最近开始阅读OOP javascript，作者似乎跳过的一件事是当声明了对象A时，突然我看到"A.prototype.constructor = A;例如
I've recently started reading up on OOP javascript and one thing that authors seem to skip over is when an object A has been declared and suddenly I see "A.prototype.constructor =A; For example,
var A = function(){}; // This is the constructor of "A"
A.prototype.constructor = A;
A.prototype.value = 1;
A.prototype.test = function() { alert(this.value); }
var a = new A(); // create an instance of A
alert(a.value); // => 1
因此，我在萤火虫中运行命令"var A = function(){};"然后显示"A.Constructor"，它是一个函数.我了解这一点.
我运行代码"A.prototype.constructor = A;"并且我认为这会将A构造函数从Function更改为A.
So I run the command in firebug "var A = function(){};" and then "A.Constructor" Which reveals it's a function. I understand this.
I run the code "A.prototype.constructor = A;" and I thought this changes the A constructor from Function to A.
A的构造函数属性已更改，对吗?相反，当我运行"A.constructor"时，它仍然给我函数().
The constructor property of A has been changed right? Instead when I run "A.constructor" it gives me function () still.
有什么意义?
我还看到了A.constructor.prototype.constructor.prototype ..这是怎么回事?
I also see A.constructor.prototype.constructor.prototype.. what is going on?
推荐答案
如果A使用A.prototype = new B();继承B，则需要使用A.prototype.constructor=A;重置类A的构造函数属性，否则A的实例将具有构造函数的B.
If A inherit B using A.prototype = new B();, you need to reset the constructor property for the class A using A.prototype.constructor=A;, otherwise instances of A would have a constructor of B.
在您的情况下，A.prototype.constructor === A将返回true，因此A.prototype.constructor = A什么也不做.
In your case, A.prototype.constructor === A will return true, so A.prototype.constructor = A did nothing.
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