let myFirstPromise = new Promise((resolve, reject) => {
  /* do something asynchronous
     which eventually calls either:
     resolve(someValue); // fulfilled
     or
     reject("failure reason"); // rejected
  */

  setTimeout(function(){
    resolve("success!"); // Yay! Everything went well!
  }, 250);
});

myFirstPromise.then((successMessage) => {
  /* successMessage is whatever we passed
   in the resolve(...) function above.
   It can be any type of object. */
  console.log("Yay! " + successMessage);

}).catch((error) => {
  /* error is whatever we passed
   in the reject(...) function. */
  console.log(error);
});