PromiseArray.js

var promiseArray = [];
    
function foo(i) {
  var def = $.Deferred();
  // This line represents some async code: ajax, setTimeout, etc
  setTimeout(function() {def.resolve(i); }, i);
  // Return the promise which may not be resolved yet
  return def.promise();
}

// Push several promises (typically this is a loop of N items)
promiseArray.push(foo(200));
promiseArray.push(foo(700));
promiseArray.push(foo(20));

// $.when() takes promise arguments and fires done when all promises are done
// Using func.apply() allows us to pass an array of N promises!
$.when.apply($, promiseArray).done(function (data) {
  // The first argument is the first return value is the 
  console.log(data); // prints 200
  // Using the magic `arguments` variable, we can get all returned values!
  console.log(arguments); // prints [200,700,20]
});