来自多个对象的javascript继承

问题描述

我不太熟悉javascript继承，我试图让一个对象从另一个继承，并定义自己的方法：

I'm not very well aquainted with javascript inheritance, and I'm trying to make one object inherit from another, and define its own methods:

function Foo() {}
Foo.prototype = {
    getColor: function () {return this.color;},
};
function FooB() {}
FooB.prototype = new Foo();
FooB.prototype = {
    /* other methods here */
};

var x = new FooB().getColor();

然而，第二个覆盖第一个（ FooB.prototype = new Foo（）被取消）。有没有办法解决这个问题，或者我的方向是错误的？

However, the second one overwrites the first one(FooB.prototype = new Foo() is cancelled out). Is there any way to fix this problem, or am I going in the wrong direction?

提前致谢，对不起任何不好的术语感到抱歉。

Thanks in advance, sorry for any bad terminology.

推荐答案

每个对象只能有一个原型，所以如果你想在继承（复制）它之后添加到原型，你必须扩展它而不是分配一个新的原型。示例：

Each object can only have one prototype, so if you want to add to the prototype after inheriting (copying) it, you have to expand it instead of assigning a new prototype. Example:

function Foo() {}

Foo.prototype = {
    x: function(){ alert('x'); },
    y: function(){ alert('y'); }
};

function Foo2() {}

Foo2.prototype = new Foo();
Foo2.prototype.z = function() { alert('z'); };

var a = new Foo();
a.x();
a.y();
var b = new Foo2();
b.x();
b.y();
b.z();

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