Multi inheritance in JS

inheritance.js

var A = function()
{
	
}
,B = function()
{
	
}
,C = function()
{
}
,createProto = function()
{
	var protos = [].slice.call(arguments)
	,prototype = {};

	protos.forEach(function(proto)
	{
		Object.keys(proto).forEach(function(key)
		{
			prototype[key] = proto[key];
		});
	});

	return prototype;
};

A.prototype = {
	constructor: A
	,metoda1: function() {}
	,metoda2: function() {}
};

B.prototype = {
	constructor: B
	,metoda3: function() {}
	,metoda4: function() {}
};



C.prototype = createProto(A.prototype, B.prototype);

var c = new C();

console.log(c instanceof A, c instanceof B, c instanceof C);

C.prototype = new B();

c = new C();

console.log(c instanceof B, c instanceof C);