fluent-promises.js

// Demonstration that promises do not involve the pyramid of doom.
// Native ES6 promises - you could do it with bluebird promises too,
// in which case Promise.delay is a built-in convenience method

function delays() {
  return delay(100).then(function() {
    return delay(100);
  }).then(function() {
    return delay(100);
  }).then(function() {
    return delay(100);
  }).then(function() {
    return delay(100);
  });
}

// Use it to delay 5 times
delays().then(function() {
  // Runs AFTER the delays
}).catch(function(e) {
  // Runs if one of the delays throws an error
});
console.log('I run too soon because we did not use then');

// Let's actually implement delay since we're not using bluebird
function delay(msec) {
  return new Promise(function(resolve, reject) {
    setTimeout(resolve, msec);
  });
}