A better javascript namespace/module pattern

app.js

app = (function () {
    var Namespace = function () {
    }

    var Module = function () {
    }

    Namespace.prototype.createModule  = function () {
        var m = new Module;
        if(arguments.length > 0)
            m.extend.apply(m, Array.prototype.slice.apply(arguments));
        return m;
    };

    Module.prototype.extend = function (fn) {
        var argArray,
            results,
            resultKey,
            namespace = this;

        argArray = Array.prototype.slice.apply(arguments).slice(1);

        this._private = this._private || {};
        results = fn.apply(this._private, argArray);
        for(resultKey in results) {
            if(results.hasOwnProperty(resultKey)) {
                namespace[resultKey] = results[resultKey];
            }
        }
        return this;
    }

    var app = new Module();
    app.namespace = function (ns) {
        return ns ? ns : new Namespace();
    }
    app.createModule = Namespace.prototype.createModule;  // app is special since it is both a module (for functionality) and a scope

    return app;
}());