Namespaced Methods for [built-in types] in JavaScript

nsProto.js

function extendPrototype(Class, name, obj) {
    var nsProto = {},
        self = null;

    for (var prop in obj) {
        if(!obj.hasOwnProperty(prop)) continue;

        Object.defineProperty(nsProto, prop, {
            enumerable: true,
            configurable: false,
            get : function() {
                return function() {
                    return obj[prop].apply(self, arguments);
                };
            }
        });
    }

    Object.defineProperty(Class.prototype, name, {
        enumerable: false,
        configurable: false,
        get : function() {
            self = this;
            return nsProto;
        }
    });
};

extendPrototype(String, "utils", {
    append : function(tail) {
        return this + tail;
    }
});

extendPrototype(Number, "rubish", {
    times : function(callback) {
        var n = this;
        for (var i = 0; i < n; ++i) {
            callback();
        }
    }
});

// Example
2..rubish.times(function() {
    console.log("One more iteration");
    console.log('Hello'.utils.append(' World'));
    console.log('Hello'.utils.append(' World')
                       .utils.append('!'));
});