A Mootools implementation of Def.js - a Ruby-like extend syntax
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This is an extendtion to Class that allows extending Classes in a ruby like syntax. This implementation was inspired by the very cool Def.js lib.

How to use

Simple Use

To create a new Class from scratch, we can use both the default Class construction method, or like this:

new Class.def("Preson") << new Class({
    initialize : function(name){
        this.name = name;
        console.log('My Name Is '+name+' And I Am '+this.power+' strong!');
   ,power : 1

To extend a Class (this can be done with any Class):

new Class.def('Ninja') << new Person({
    power :20

new Person('Bob'); //My Name is Bob And I Am 1 strong!
new Ninja('Lee'); //My Name Is Lee and i am 20 strong!

NOTE: It is very important that you use the new operator on both, or the execution order will get break

This should work on any instance of Class, no matter how it was defiened.


  1. You must make sure you use the new operator for both the Class.def and the inherited Class.
  2. Make sure you never call Class.def without using the full syntax (<< new Class). Doing so might make the following Class instantiation fail.
  3. I have obviosly not tested this too much, so use with caution.

Notes On version 1.1

  1. You can now only create Classes using the << operator (well, actually, any numeric operator will do).
  2. You can no longer create Classes via passing a second argument. This is to make sure the syntax is used correctly.