Crossbreed.js - Multiple Inheritance in Javascript

Given Javascript (ES5) doesn't even have classical inheritance, how greedy I must be to want multiple inheritance.

At just over 100 lines of code, this featherweight JS library can do what most OOP languages can't.

---

Creating a Class

First, create a Class by passing in a name and properties. If provided, the "initialize" method will be called as a constructor.

Class.create( "Pony", {

	name: "My Name",
	info: "I'm a pony",

	initialize: function(name){
		this.name = name;
	},
	addInfo: function(info){
		this.info += " "+info;
	},
	speak: function(){
		alert(this.name+" speaking, "+this.info);
	}

});

var Applejack = new Pony("Applejack"); 
Applejack.speak(); // Applejack speaking, I'm a pony

Single Inheritance

To extend from a Class, include an "is" property with the name of the parent Class. Calling this.super() within a function will invoke the parent Class's method of the same name.

Class.create( "Unicorn", {
	is: "Pony",
	initialize: function(name){
		this.super(name);
		this.addInfo("who's magical");
	}
});

var Rarity = new Unicorn("Rarity"); 
Rarity.speak(); // Rarity speaking, I'm a pony who's magical

Class.create( "Pegasus", {
	is: "Pony",
	initialize: function(name){
		this.super(name);
		this.addInfo("who can fly");
	}
});

var Fluttershy = new Pegasus("Fluttershy");
Fluttershy.speak(); // Fluttershy speaking, I'm a pony who can fly

Multiple Inheritance

Now the juicy part... To extend from multiple Classes, include an Array of parent Class names. Invoking this.super[ParentClass] will call that parent Class's method.

Class.create( "Alicorn", {
	is: ["Unicorn", "Pegasus"],
	initialize: function(name){
		this.super.Unicorn(name);
		this.addInfo("AND");
		this.super.Pegasus(name);
	}
});

var Celestia = new Alicorn("Celestia");
Celestia.speak(); // Celestia speaking, I'm a pony who's magical AND who can fly

That's all the practical usage I'll ever need.