javascript是否支持C ++等多重继承 [英] does javascript support multiple inheritance like C++

问题描述

我知道如何在javascript中继承，但我只能继承一个对象。
例如。

i know how to do inheritance in javascript but i can only inherit a single object. eg.

function fun1() {
this.var1=10;
this.meth1=function() {
...
...
};
}

function fun2() {
this.var2=20;
this.meth2=function() {
...
...
};
}

function fun3() {
this.var3=30;
this.meth3=function() {
...
...
};
}

现在如果我想要 fun3 继承对象 fun1 对象我可以这样做

now if i want an fun3 object to inherit fun1 object i can do this

fun3.prototype=new fun1();

或继承 fun2 我可以做的对象这个

or to inherit fun2 object i can do this

fun3.prototype=new fun2();

但我怎样才能继承 fun1 和 fun2 ？

推荐答案

从技术上讲，JavaScript不提供多重继承。每个对象都有一个明确定义的单个原型对象，因此是一个原型链。

Technically, JavaScript does not offer multiple inheritance. Each object has a well-defined single "prototype" object, and thus a "prototype chain".

但是，可以用其他方法扩充任何对象，所以 - 称为expandos。因此，您可以迭代一组方法，并将它们单独添加到新创建的对象中。这样的集合称为mixin。

However, it is possible to augment any object with additional methods, so-called "expandos". So you could iterate over a collection of methods and individually add them to newly created objects. Such a collection is called "mixin".

几个框架提供mixins，例如：

Several frameworks offer mixins, for example:

• qooxdoo


• ExtJS


• mootools


• ...

• qooxdoo
• ExtJS
• mootools
• ...

它们的工作方式基本相同。

They all work pretty much the same.

但请注意，这不是真正的继承，因为更改mixin不会反映在对象中。

Note however that this is not real inheritance, since changes to the mixin will not be reflected in the objects.

例如：

var mixin = {
    method: function () {
        console.log('Hello world!');
    }
};
var foo = new fun1();
foo.method = mixin.method;
foo.method(); // Hello world!
mixin.method = function () { console.log('I changed!') };
foo.method(); // Hello world!

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