mb-extend

Super-lightweight inheritance framework for JavaScript.

Installation

Include mb-extend.js

<script src='/path/to/mb-extend.js></script>

(Optional) Enable unsafe mode, which makes the framework much easier to use, but may create unintended side-effects if used with other libraries.

mb.extend.unsafe()

Usage

There are no changes to defining normal prototypes/classes

var Vehicle = function(make, model, wheels, doors) {
    this.make = make;
    this.model = model;
    this.wheels = wheels;
    this.doors = doors;
};
Vehicle.prototype.identify = function() {
    return this.make + ' ' + this.model;
};

Usafe - unsafe mode

Extending a class:

var Car = Vehicle.extend(function(make, model) {
    // ...
});

Calling the parent's constructor

var Car = Vehicle.extend(function(make, model) {
    this.super(make, model, 4, 4);
});

Usage - safe mode

Extending a class:

var Car = mb.extend(Vehicle, function(make, model) {
    // ...
});

Calling the parent's constructor

var Car = mb.extend(Vehicle, function(make, model) {
    mb.extend.super(this, make, model, 4, 4);
});

Why Extend?

By extending a class, your subclass is now an instance of both its constructor and its parent's constructor.

var car = new Car('Honda', 'Accord');

console.log( car instanceof Car );      // true
console.log( car instanceof Vehicle );  // true

This means that you will also have access to any methods of the superclass

var car = new Car('Honda', 'Accord');

console.log( car.identify() );      // Honda Accord

Any instances of your subclass will also have access to the parent class via instance.parent

var car = new Car('Honda', 'Accord');

console.log( car.parent == Vehicle );   // true

Contact & License Info

Author: Matthew Balmer
Twitter: @mattbalmer
Website: http://mattbalmer.com
License: MIT