Proto, a Selfish variant

gistfile1.js

////////// API //////////
// Code by Axel Rauschmayer
// Based on Selfish https://github.com/Gozala/selfish

// To be part of ECMAScript.next
if (!Object.getOwnPropertyDescriptors) {
    Object.getOwnPropertyDescriptors = function (obj) {
    	var descriptors = {};
    	Object.getOwnPropertyNames(obj).forEach(function (prop) {
    		descriptors[prop] = Object.getOwnPropertyDescriptor(obj, prop);
    	});
    	return descriptors;
    };
}

var Proto = {
    new: function () {
        // new this.constructor() does not let us hand in the arguments
        // => we have to simulate it
        var instance = Object.create(this);
        if (instance.constructor) {
            instance.constructor.apply(instance, arguments);
        }
        return instance;
    },
    extend: function (props) {
        // We cannot set the prototype of "properties"
        // => copy them to a new object that has the right prototype
        var subProto = Object.create(this, Object.getOwnPropertyDescriptors(props));

        // Ensure that constructor and prototype point to each other
        if (subProto.constructor) {
            subProto.constructor.prototype = subProto;
        }
        subProto.super = this; // for super-calls
        return subProto;
    }
};