在JavaScript中对具有必需参数的类进行子类化 [英] Subclassing a class with required parameters in JavaScript

问题描述

如果在JavaScript中对class进行子类化是这样完成的：

If subclassing a "class" in JavaScript is done like so:

var ParentClass = function() {
    // something
};


var ChildClass = function() {
    // something
};

ChildClass.prototype = new ParentClass();

...如果父类需要参数，我该怎么办？

... what should I do when the parent class has required parameters?

var ParentClass = function(requiredParameter) {
    if (typeof requiredParameter === 'undefined') {
        throw new TypeError("'requiredParameter' is required!");
    }
};


var ChildClass = function() {
    // something
};

ChildClass.prototype = new ParentClass();
// ^ Throws TypeError

谢谢。

推荐答案

将它改为类似：

function clone (obj) {
  if (!obj) return;
  clone.prototype = obj;
  return new clone();
}

var ParentClass = function() {
    // something
};


var ChildClass = function() {
    // something
};

ChildClass.prototype = clone(ParentClass.prototype);
ChildClass.prototype.constructor = ChildClass; // if you want

现在你不必担心它，因为你没有必须调用父构造函数将其子类化：）

Now you don't have to worry about it, because you don't have to call the parent constructor to subclass it :)

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