animation-frame.js

/**
 * `window.requestAnimationFrame` rewritten in `Promise`s way.
 * See https://api.dartlang.org/1.12.2/dart-html/Window/animationFrame.html
 */

const animationFrame = () => new Promise(resolve => window.requestAnimationFrame(resolve));

function test(prefix, fn) {
  var counter = 0;
  const next = function() {
    if (counter++ < 10) {
      //console.log(prefix + ': did step ' + counter);
      return fn(next);
    }
  };
  return next();
}

test('PROMISE', function(step) {
  animationFrame().then(function(t) {
    console.log('promise' + t);
    step();
  });
});

test('REQUEST', function(step) {
  requestAnimationFrame(function(t) {
    console.log('request' + t);
    step();
  });
});