es-class

es-class

A future proof, backward compatible, JavaScript class utility.

• ES6 and ES7 friendly, through semantic extends and constructor plus other features
• ES5 natively compatible granting that what you write is what you get
• ES3 backward compatible, thanks to common minifiers that will make production code safe

Feel free to test all features related to this project, and please come back if your browser is not green.

Compatibility

Following a list of tested browsers split in Desktop and Mobile.

Desktop

• IE 6 or greater
• Firefox 3 and greater
• Chrome
• Safari
• Opera

Mobile

• Android 2 or greater
• iOS 5 or greater
• IE9 Mobile or greater
• Bada
• Kindle Fire
• Xpress
• Opera Mini and Mobile
• Blackberry
• Ubuntu Phone

Features

All features explained in the dedicated page.

Following a summary:

• constructor to optionally define the implicit initializer per each instance
• extends to optionally define a class or an object to inherit from
• super to shortcut super methods invocation
• with to attach lightweight traits / mixins enabling composition behind optional initializers per each mixin
• static to define public static class constants, inherited if extended, without ever polluting the prototype
• implements to perform light checks over expected implementations and warn eventually when something is missing

Features Example

This is an example of what's possible:

var Engineer = Class({
  extends: Person,
  with: [
    eventEmitter,
    growingEachYear,
    carrierPath
  ],
  implements: [
    iWorker
  ],
  static: {
    SOFTWARE: 0,
    CONSTRUCTIONS: 1
  },
  constructor: function (name, age, type) {
    this.super(name, age);
    this.type = type;
  }
});

var me = new Engineer(
  'Mr. Andrea Giammarchi',
  36,
  Engineer.SOFTWARE
);

me instanceof Person; // true
me.type;              // Engineer.SOFTWARE

me.emit('work:start', {
  tasks: ['do this', 'do that']
});

ES6 Ready

Using Babel it is possible to make your code directly compatible down to ES5 or even ES3 without loosing the ability to debug in every platform without needing source-map. What you see is basically what you get.

// how you would write in native ES6
class B extends A {
  method(x, y) {
    return super.method(x, y);
  }
  get value() {
    return super.value;
  }
  set value(value) {
    super.value = value;
  }
}

// how you would write in es-class
var B = Class({ extends: A,
  method(x, y) {
    return this.super(x, y);
  },
  get value() {
    return this.super();
  },
  set value(value) {
    return this.super(value);
  }
});

A simple call to babel --whitelist=es6.arrowFunctions,es6.properties.shorthand f.js and the output will be way cleaner than any automation produced by the same transpiler.

Your output will be more readable and also probably faster at execution time.

ES7 Ready

Looking at the future, grouped static properties and lightweight traits are also in, giving the ability to compose classes through eventual traits initialization without being on the way after class definition.

var wheels = {
  init: function () {
    if (this instanceof Car) {
      this.frontWheels = 2;
      this.rearWheels = 2;
    } else {
      this.frontWheels = 1;
      this.rearWheels =
        this instanceof Tricycle ? 2 : 1;
    }
  },
  turn: function (where) {
    console.log('turning ' + where);
  }
};

var engine = {
  hp: 120
};

var Car = Class({
  with: [
    wheels,
    engine
  ]
});

var c = new Car;
c.turn('left'); // trning left
c.hp;           // 80

Which File ?

• as global to include inline or before any other file that uses classes
• require/CommonJS to include it via browserify or node.js
• AMD module if you want to load it via AMD

You can also simply npm install -g es-class and use var Class = require('es-class'); whenever you need it.

License

MIT Style License