Xamlizer - a way to implement INotifyPropertyChang* in JavaScript!

fiddle.js

var xamlizer = (function() {
    'use strict';
    var __hasOwn = Object.prototype.hasOwnProperty;

    var propSkeleton = function() {
        this.enumerable = true;
        this.configurable = true;
        //this.writable = true;
    };


    return function(o) {
        var propertyChanging, propertyChanged, prop, value,
            locals = {},
            _propertyChanged = [],
            _propertyChanging = [];

        propertyChanging = function(name) {
            for(var i = 0, il = _propertyChanging.length; i < il; i++) {
                _propertyChanging[i](o, name);
            }
        };

        propertyChanged = function(name) {
            for(var i = 0, il = _propertyChanged.length; i < il; i++) {
                _propertyChanged[i](o, name);
            }
        };

        for(var name in o) {
            if (!__hasOwn.call(o, name)) {
                continue;
            };

            (function (name) {
                prop = new propSkeleton();
                prop.get = function() {
                    return locals[name];
                };
                prop.set = function(val) {
                    if(val !== locals[name]) {
                        propertyChanging(name);
                        locals[name] = val;
                        propertyChanged(name);
                    }
                }
                value = o[name];
                Object.defineProperty(o, name, prop);
                o[name] = value;
            })(name);
        }

        o.addPropertyChanged = function(fn) {
            _propertyChanged.push(fn);
        };

        o.addPropertyChanging = function(fn) {
            _propertyChanging.push(fn);
        };

        o.removePropertyChanged = function(fn) {
            var index = _propertyChanged.indexOf(fn);

            if(index >= 0) {
                _propertyChanged = _propertyChanged.slice(0, index).concat(_propertyChanged.slice(index + 1, _propertyChanged.length));
            }
        };

        o.removePropertyChanging = function(fn) {
            var index = _propertyChanging.indexOf(fn);

            if(index >= 0) {
                _propertyChanging = _propertyChanging.slice(0, index).concat(_propertyChanging.slice(index + 1, _propertyChanging.length));
            }
        };
   };
})();