Inheritance pattern

extend_inherit.js

(function (namespace) {
    "use strict";

    function Class() {}

    Class.prototype = {
        constructor: Class
    };
    Class.extend = function (fn) {
        if (!fn.name) {
            fn.name = fn.toString()
                .replace(/function |\([^\0]+/g, "") || "anonymous";
        }
        namespace[fn.name] = fn;
        fn._super = this;
        fn.extend = this.extend;
        fn.inherit = this.inherit;
        fn.prototype = new fn._super();
        fn.prototype.constructor = fn;
        return fn;
    };
    Class.inherit = function (obj) {
        for (var o in obj) {
            if (obj.hasOwnProperty(o)) {
                this.prototype[o] = obj[o];
            }
        }
        return this;
    };

    namespace.Class = Class;
}(this));

Class.extend(function A() {
    if (this.constructor === A) {
        this.step1();
    }
}).inherit({
    step1: function () {
        this._step1 = 1;
    },
    aMethod: function () {}
}).extend(function B() {
    B._super.apply(this, arguments);
    if (this.constructor === B) {
        this.step2();
    }
}).inherit({
    step2: function () {
        this._step2 = 2;
    },
    bMethod: function () {}
}).extend(function C() {
    C._super.apply(this, arguments);
    if (this.constructor === C) {
        this.step3();
    }
}).inherit({
    step3: function () {
        this._step3 = 3;
    },
    cMethod: function () {}
});
var c = new C();

/*
note: 
* object c is an instance of A, instance of B, and instance of C
* object c has the _step1, _step2, and _step3 properties (but not all at the object level)
* object c has all inherited and extended methods

*/