promise_decorator.js

promise_decorator.js

function decorator(context, callbacks){
      return (function(context, callbacks, $finally) {
        function execute(callbacks, context, args, value) {
            return callbacks.length ? 
                execute(callbacks, context, args, callbacks.pop().apply(context, args, value)) || value:value;
        };
  
        return {
            context: context,
            invoke: function(fn, args, context){
                var value;
                $finally.apply(this, [(value=execute([].concat(callbacks), context||this.context||this, args, 
                    fn.apply(context||this, args))), args]);
                return value;
            },
            then: function(callback){
                typeof(callback)==='function' && callbacks.unshift(callback);
                return this;
            },
            finally: function(onFinally){
                $finally=onFinally;
                return this;
            }
        };
  })(context||this, callbacks||[], function(){})
};