OOP in javascript extracted from CoffeeScript

coffeescript-extend.js

// tiny JavaScript inheritance
// extracted from CoffeeScript
// 
// * **param:** {Class} child
// * **param:** {Class} parent
var extends = function( child, parent ) { 
    for ( var key in parent ) { 
      if ( {}.hasOwnProperty.call( parent, key ) ) {
        child[ key ] = parent[ key ];
      }
    } 
    
    function ctor() { 
      this.constructor = child; 
    } 

    ctor.prototype = parent.prototype; 
    child.prototype = new ctor(); 

    child.__super__ = parent.prototype; 
    return child; 
}