shakakira / class.js

Lightning fast class system. Beautiful API. Rock solid debugging. 0.6 kb

Class.js

Lightning fast JavaScript class system in 1KB (588 bytes gzipped)

100% no wrappers, same performance as hand-written pure JS classes. Exposes a beautiful API and gives classes and methods speaking names for debugging!

inspired by [my.class.js] (https://github.com/jiem/my-class) -> Heavily optimized for google closure advanced compilation.

more details to performance:

• [instantiation perfs] (http://jsperf.com/moo-resig-ender-my)
• [inheritance perfs - calling super constructor] (http://jsperf.com/moo-resig-ender-my/2)
• [inheritance perfs - calling super method] (http://jsperf.com/moo-resig-ender-my/3)

Create a class

(function() {
    
  Class.design('lib.Person', {

    STATIC: {
      AGE_OF_MAJORITY: 18
    },

    initialize: function(name, age) {
      this.name = name;
      this.age = age;
    },

    sayHello: function() {
      console.log('Hello from ' + this.name + '!');
    },

    drinkAlcohol: function() {
      this.age < lib.Person.AGE_OF_MAJORITY ?
        console.log('Too young! Drink milk instead!') :
        console.log('Whiskey or beer?');
    }
  });
})();

var john = new lib.Person('John', 16);
john.sayHello(); //log "Hello from John!"
john.drinkAlcohol(); //log "Too young! Drink milk instead!"

Extend and Implement other Classes

(function() {
  Class.design('lib.Dreamy', {
    dream: 'default',
      
    describeDream: function() {
      return "..it is about: " + this.dream;
    }
  });
})();
    
(function() {
  Class.design('lib.Awakable', {
    wakeUp: function() {
      console.log('Wake up!');
    }
  });
})();
    
(function() {
  var Dreamer = Class.design('lib.Dreamer', { 
    Extends: lib.Person, // person is super class (prototypal inheritance)
    Implements: [lib.Dreamy, lib.Awakable], // mixin prototypes of other classes

    initialize: function(name, age, dream) {
      Dreamer.Super.call(this, name, age);
      this.dream = dream;
    },

    sayHello: function() {
      Dreamer.Super.prototype.sayHello.call(this);
      console.log('I dream of ' + this.describeDream() + '!');
    }
  });
})();

var sylvester = new lib.Dreamer('Sylvester', 30, 'eating Tweety');
sylvester.sayHello(); //log "Hello from Sylvester! I dream of eating Tweety!"
sylvester.wakeUp(); //log "Wake up!"

Add methods to a class

Class.extend(my.lib.Dreamer, {

  touchTheSky: function() {
    console.log('Touching the sky');
  },

  reachTheStars: function() {
    console.log('She is so pretty!');
  }

});

Afraid to forget the new operator?

var Person = Class.design({

  // you can now call the constructor with or without new
  initialize: function(name, city) {
    if (!(this instanceof Person)) return new Person(name, city);
    
    this.name = name;
    this.city = citye;
  }

});

AMD Usage

Using Class.js in AMD will look like the following:

define('TagTrack', ['Track', 'Class'], function (Track, Class) {
    var TagTrack = Class.design('TagTrack', {
        Extends: Track,
        initialize : function(settings){
            TagTrack.Super.call(this, settings);
            this.settings = settings
        }
    });
    return TagTrack;
});