javascript“多态可调用对象”

I saw 这篇关于多态可调用对象的文章 http://ajaxian.com/archives/javascript-tips-for-rookies-and-gurus并试图让它工作，但似乎它们并不是真正的多态，或者至少它们不尊重原型链。

这段代码打印undefined, not "hello there".

这种方法不适用于原型，还是我做错了什么？

var callableType = function (constructor) {
  return function () {
    var callableInstance = function () {
      return callableInstance.callOverload.apply(callableInstance, arguments);
    };
    constructor.apply(callableInstance, arguments);
    return callableInstance;
  };
};

var X = callableType(function() {
    this.callOverload = function(){console.log('called!')};
});

X.prototype.hello = "hello there";

var x_i = new X();
console.log(x_i.hello);

你需要改变这个：

var X = callableType(function() {
    this.callOverload = function(){console.log('called!')};
});

to this:

var X = new (callableType(function() {
    this.callOverload = function(){console.log('called!')};
}));

注意new以及周围的括号callableType调用。

括号允许callableType被调用并返回函数，该函数用作构造函数new.

EDIT:

var X = callableType(function() {
    this.callOverload = function() {
        console.log('called!')
    };
});

var someType = X();      // the returned constructor is referenced
var anotherType = X();   // the returned constructor is referenced

someType.prototype.hello = "hello there";  // modify the prototype of
anotherType.prototype.hello = "howdy";     //    both constructors

var some_i = new someType();           // create a new "someType" object
console.log(some_i.hello, some_i);

var another_i = new anotherType();     // create a new "anotherType" object
console.log(another_i.hello, another_i);

someType();      // or just invoke the callOverload
anotherType();

我真的不知道你如何/在哪里/为什么使用这种模式，但我想有一些很好的理由。