动态修改构造函数在JavaScript中？ [英] Dynamically modifying Constructors in JavaScript?

问题描述

我在找做一些有点奇特在JavaScript中构造函数，我不太清楚如何做到这一点。

I'm looking to do something a little bit fancy with constructor functions in Javascript, and I'm not quite sure how to do it.

我希望能够像这样定义构造函数，然后将它们传递到另一个函数（一个修改器）：

I want to be able to define Constructor functions, and then pass them into another function (a "modifer") like this:

function OriginalConstructor() {
    // Do constructor things here
    // Like defining methods and properties
}

NewConstructor = modifyConstructor(OriginalConstructor);

和由此产生的NewConstructor应该是功能上等同于这样的：

And the resulting "NewConstructor" should be functionally equivalent to this:

function NewConstructor(id, data) {
    this.id = id;
    this.data = data;
    // Do stuff from the original constructor here
    // i.e. the same methods and properties defined in the original constructor
}

有谁知道如何去打造modifyConstructor功能？

Does anybody know how to go about creating the "modifyConstructor" function?

推荐答案

您创建为您定义并调用原来的构造函数设置属性的功能。例如：

You create a function that sets the properties as you defined and calls the original constructor. For example:

function modifyConstructor(Constr) {
    function NewConstructor(id, data) {
        this.id = id;
        this.data = data;

        // Call original constructor
        Constr.apply(this, Array.prototype.slice.call(arguments, 2));
    }
    // Setting the constructor property might not be a good idea depending on
    // the use case
    NewConstructor.prototype = Object.create(Constr.prototype, {
        constructor: {value: NewConstructor, writable: true, configurable: true}
    });
    return NewConstructor;
}

这实质上是实现 NewConstructor 作为一个子类，无论构造方法是

This basically implements NewConstructor as a subclass of whatever Constr is.

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