uberproto

Uberproto is a simple base object that adds some sugar to ECMAScript 5 style object inheritance in JavaScript.

Here is what it can do in a nutshell:

• Easily extend objects
• Initialization methods
• Super methods
• Mixins
• Method proxies

With a small footprint (0.8Kb minified and 0.4Kb compressed) and an easy to handle API of just four methods it also doesn't add a lot of baggage to your JavaScript application.

Usage

UberProto can be used as a CommonJS AMD module (e.g. with RequireJS), NodeJS or directly in the browser. If no module loader is available, the global variable Proto will be defined after you include the script. To be compatible with all browsers, you also need the ES5-shim.

Using AMD (e.g. RequireJS)

Make sure proto.js is in the right folder and then just define a module like this:

define(['proto'], function(Proto) {
	// Source goes here
});

Straight in the browser

<script type="text/javascript" src="http://cdnjs.cloudflare.com/ajax/libs/es5-shim/1.2.4/es5-shim.min.js"></script>
<script type="text/javascript" src="proto.min.js"></script>

Now Proto is available as a global vairable.

With NodeJS

After installing the package using NPM

npm install uberproto

just require it like any other module:

var Proto = require('uberproto');

Creating objects

Extend

You can extend any UberProto object by using extend to create a new object that inherits from the current one. Internally Object.create is being used and the prototype is set to the object that you are extending. If defined, the init method will be used as the constructor. That way you can define a simple Person object (which will be reused throughout the next paragraphs):

var Person = Proto.extend({
	init : function(name)
	{
		this.name = name;
	},
	
	fullName : function()
	{
		return this.name;
	}
});

Initialize

You can create a new instance by calling create:

var dave = Person.create('Dave');
console.log(dave.name); // -> 'Dave'
console.log(dave.fullName()); // -> 'Dave'

Overwriting create is great if you want to customize the way objects are being instantiated.

Super methods

In each method this._super refers to the method being overwritten, if there is one. For our Person object, for example, it would be a lot better if it also had a last name:

var BetterPerson = Person.extend({
	init : function(name, lastname)
	{
		// If you want to pass all original arguments to the
		// _super method just use apply:
		// this._super.apply(this, arguments);
		
		this._super(name);
		this.lastname = lastname;
	},
	
	fullName : function()
	{
		return this._super() + ' ' + this.lastname;
	}
});

var dave = BetterPerson.create('Dave', 'Doe');
console.log(dave.name); // -> 'Dave'
console.log(dave.lastname); // -> 'Doe'
console.log(dave.fullName()); // -> 'Dave Doe'

Mixins

Mixins add functionality to an existing object. Mixins can also access their super methods using this._super. This will either refer the overwritten method on the object itself or the one on the prototype:

Person.mixin({
	init : function()
	{
		this._super.apply(this, arguments);
		this.can_sing = true;
	},
	
	sing : function()
	{
		return 'Laaaa';
	}
});

var dude = Person.create('Dude');
console.log(dude.sing()); // -> 'Laaaa'
console.log(dude.can_sing); // -> true

Actual instances can be mixed in just the same:

var operaSinger = Person.create('Pavarotti');
operaSinger.mixin({
	sing : function()
	{
		return this._super() + ' Laalaaa!';
	}
});

console.log(operaSinger.sing()); // -> 'Laaaa Laalaaa!

Method proxy

You can create proxy callbacks, that make sure that this will always point to the right object:

var callback = operaSinger.proxy('fullName');
console.log(callback()); // -> 'Pavarotti'

Extending existing objects

Although it is the default functionality, you don't have to inherit from the UberProto base object to use it's functionality. extend, mixin and proxy are all able to take an existing object as the second parameter:

var Person = {
	fullName : function()
	{
		return this.name;
	}
};

Mixin

// Mix in a setName method.
Proto.mixin({
	setName : function(name) {
		this.name = name;
	}
}, Person);

// Create a new Person instance
var instance = Object.create(Person);
instance.setName('Dude');
console.log(instance.fullName()); // -> Dude

// Create a proxy
var callback = Proto.proxy('fullName', instance);
console.log(callback()); // -> Dude

// Extend Person and return the extended object
// _super works as usual for extend and mixin
var Extended = Proto.extend({
	fullName : function()
	{
		return this.lastname + " " + this._super();
	},

	setName : function(name, lastname)
	{
		this._super(name);
		this.lastname = lastname;
	}
}, Person);

var extendedInstance = Object.create(Extended);
extendedInstance.setName('Dude', 'The');
console.log(extendedInstance.fullName()); // -> The Dude

To use the init constructor method you can simply call create:

var Person = {
	init : function(name) {
		this.name = name;
	}
}

var instance = Proto.create.call(Person, 'Dude');