generators.js

function getDataPromise () {
  var random = Math.random() * 5000 | 0;
  return new Promise(function (resolve, reject) {
    setTimeout(function () {
       resolve(random);
    }, random);
  });
}

function runner (generator) {
  var iterator = generator();
  
  function onNext (next) {
    if (next.done) {
      return;
    }
    next.value.then(function (value) {
      onNext(iterator.next(value));
    });
  }

  onNext(iterator.next());
}

function* showDataInOrder () {
  var r1 = yield getDataPromise();
  console.log('r1: ', r1);

  var r2 = yield getDataPromise();
  console.log('r2: ', r2);

  var r3 = yield getDataPromise();
  console.log('r3: ', r3);
}

runner(showDataInOrder);