simple promises demonstration for Yoshi.

flick.js

// USAGE:
// flick(function(willBeNull, next) { next("hey"); }).then(....).then(...);

var PPromise = function(callback) {
  this.thenCallback = function() {};
  this.next = function() {};
  this.data = null;
  this.resolved = false;
  this.nextPromise = null;
}

PPromise.prototype.getNextPromise = function() {
  this.nextPromise = this.nextPromise || new PPromise();
  return this.nextPromise;
};

/**
 * callback(data, nextCall)
 */
PPromise.prototype.then = function(callback) { 
  this.thenCallback = callback;
  if (this.resolved) this.callThen();
  
  return this.getNextPromise();
};

PPromise.prototype.resolve = function(data) {
  this.data = data;
  this.resolved = true;
  this.callThen();
};

PPromise.prototype.callThen = function() {
  var nextPromise = this.getNextPromise();
  return this.thenCallback(this.data, nextPromise.resolve.bind(nextPromise));
};

// Nice method for makin it easier to work with it
var flick = function(callback) {
  var promise = new PPromise();
  promise.resolve(null);
  return promise.then(callback);
};

// EXAMPLE
flick(function(data, next) {
  document.body.innerHTML = "Yoshi,";
  setTimeout(function() {
      next(" it worked after 2 seconds.");
  }, 2000);
}).then(function(data, next) {
    document.body.innerHTML += data;
    setTimeout(next, 1000);
}).then(function(data) {
    document.body.innerHTML += " aaaaaaaand finished.";
});

watch it over here: http://jsfiddle.net/rckaf6Lm/