其实例为函数的JavaScript构造函数

Question

I know this may be a bizarre question with possibly no practical application, but would it be possible to make a JavaScript class that constructs instances that behave as functions? Here's what I mean:

function Factory() {}

// this may not be necessary, but I'll include it for sake of clarification
Factory.prototype = Object.create(Function.prototype);

var method = new Factory();

method(); // Objective: should not throw TypeError

To further clarify the objective:

• method should be callable as a function
• method should be the result of calling a constructor (eg var method = new Factory() in this case)
• The constructor cannot be Function .

Answer 1

If I understand correctly. Object constructor need to return his method. Then you can call it like you describe.

function Factory() {
    return this.method;
}

Factory.prototype.method = function() {
    console.log('from method');
};

var method = new Factory();

method();

http://jsfiddle.net/ydcoL3c2/