[forwardonly2015]

AbstractDuck={
 create: function(){return Object.create(this)},
 extend: function(src){
   for(var i in src){
     if(!src.hasOwnProperty(i)) return this
     this[i]=src[i]
   }
   return this
 },
 swim: function(){console.log("I am swimming")}
}
RealDuck=AbstractDuck.create().extend({
  quack: function(){console.log("My name is "+this.name+", quack, quack.")}
})
RubberDuck=AbstractDuck.create().extend({
  quack: RealDuck.quack
})
WoodDuck=AbstractDuck.create()


;[
  RealDuck.create().extend({name: "Donald"}),
  RubberDuck.create().extend({name: "RubberDonald"}),
  WoodDuck.create().extend({name: "Woody"})
].forEach(function(duck){if(duck.quack) duck.quack()})



//My name is Donald, quack, quack.
//My name is RubberDonald, quack, quack.