Async execute forEach with Q Promise

gistfile1.js

var Q = require('q');
 
var f = function(a) {
  var defer = Q.defer();
  setTimeout(function() {
    console.log(a);
    defer.resolve(a);
  }, a);
  return defer.promise;
};
 
console.log("Start ...");
Q.all([3000,2000,1000].map(f)).then(function(result) {console.log(result)});
console.log("Lets GO !");