Promises/KISS example

promise.js

var Promise = require('futures');

function getUnavailableData(params) {
  var p = Promise.create({ updatable: true, timeout: Infinity, freeze: false });
  // p.fulfill(err, data, data, ...);
  setInterval(askUserHowHeFeelsAboutLife, 60*60*1000, p.fulfill);
  return p.protected(); // returns a different object which has no fulfill method
}

function useUnavailabledata() {
  var p = getUnavailableData();
  if (! (p instanceof Promise)) {
     throw new Error("How odd, not a promise instance");
  }
  if ('function' !== typeof p.when) {
     throw new Error("How odd, not a promise by duck-typing");
  }
  p.when(function (err, data, data, ...) {
    // store data in cache
  });
  if (p.options.updatable) {
    p.whenever(function (err, data, data, ...) {
      // update data in cache
    });
  }
  p.ready // true once resolved
}

var j = Promise.join(options);
j.add(p1, p2, p3);
or
j.add([p1, p2, p3]);