Playing around with simplifying inheritance in JavaScript. Not sure if this ill ever work, but worth playing with, I think.

inheritance.js

function forin(obj, fn) {
  
	var prop = '';
	
	for (prop in obj) {
		
		if (Object.prototype.hasOwnProperty.call(obj, prop)) {
			fn.call(null, obj[prop], prop, obj);
		}
		
	}
	
}

function enhance(source, extra) {

	var created     = Object.create(source),
		constructor = function () {};

	forin(extra, function (value, key) {
		
		if (key in created) {
			created['$parent_' + key] = created[key];
		}
		
		created[key] = value;
		
	});
	
	constructor.prototype = created;
	
	return constructor;
	
}

function callParent(method, context, args) {
	
	var proto       = Object.getPrototypeOf(context),
		superMethod = proto['$parent_' + method];
	
	return method.apply(context, args);
	
}

function Foo() {
	this.init();
}

Foo.prototype = {
	
	name: 'Foo',
	
	init: function () {
		console.log('Foo.init');
	}
	
};

var Bar = enhance(Foo, {

	name: 'Bar',
	
	init: function () {
		
		console.log('Bar.init');
		callParent('init', this);
		
	}
	
});

var Baz = enhance(Bar, {

	name: 'Baz',
	
	init: function () {
		
		console.log('Baz.init');
		callParent('init', this);

	}
	
});

var foo = new Foo(),
	bar = new Bar(),
	baz = new Baz();