Can a JavaScript object have a prototype chain, but also be a function?

Question

function a () {
    return \"foo\";
}

a.b = function () {
    return \"bar\";
}

function c () { };
c.prototype = a;

var d = new c();
d.b(); // returns \"bar\"
d()         


        

Answer 1

Yes, it is possible if you use the __proto__ property Daniel Cassidy mentioned. The trick is to have c actually return a function that has had a attached to its prototype chain.

function a () {
    return "foo";
}

a.b = function () {
    return "bar";
}

function c () {
    var func = function() {
        return "I am a function";
    };
    func.__proto__ = a;
    return func;
}
c.prototype = a;

var d = new c();
d.b(); // returns "bar"
d(); // returns "I am a function"

However, you'll need to do some more tweaking of the prototype chain if you want instanceof to return better results.

d instanceof c // true
d instanceof a // false
c instanceof a // false