Defers execution of the callback until exec is run. At that point, all future calls are executed immediately.

Defer.js

function Defer(callback){
  if(!this instanceof Defer)
    return new Defer(callback);

  var queue = []
    , callback = callback
    , slice = Array.prototype.slice
    , changeling = function(){
        queue.push({
          'context': this,
          'args'   : slice.call(arguments, 0)
        });
      }
    , wrapper = function(){
        changeling.apply(this, slice.call(arguments, 0));
      }
  ;//var

  wrapper.exec = function(){
    var call;
    while(call = queue.pop()){
      callback.apply(call.context, call.args);
    }

    changeling = callback;
  }

  return wrapper;
}

var func = function(x) { return x };
func.hello = function(who) { return "hey baby, " + who; }

func(10) // => 10
func.hello("chad") // => "hey baby, chad"

var func = (function() {
  var privateData = 0;

  var _func = function(x) { privateData ++; return x; };
  _func.hello = function(who) { return "you called " + privateData + " times"; }

  return _func;
})();