Decorator Pattern

gistfile1.js

// http://shichuan.github.com/javascript-patterns/

var tree = {};

tree.decorate = function(){
     console.log('Make sure the tree won\'t fall');
};

tree.getDecorator = function(deco){
     tree[deco].prototype = this;
     return new tree[deco];
};

tree.RedBalls = function(){
     this.decorate = function(){
          this.RedBalls.prototype.decorate();
          console.log('Put on some red balls');
     };
};

tree.BlueBalls = function(){
     this.decorate = function(){
          this.BlueBalls.prototype.decorate();
          console.log('Add blue balls');
     };
};

tree.Angel = function(){
     this.decorate = function(){
          this.Angel.prototype.decorate();
          console.log('An angel on the top');
     };
};

tree = tree.getDecorator('BlueBalls');
tree = tree.getDecorator('Angel');
tree = tree.getDecorator('RedBalls');

tree.decorate();