Yield Promises

yield-promise.js

function run(generator) {
  var it = generator();
  var obj = it.next();

  (function _run() {
    if (!obj.done) {
      obj.value.then(result => {
        obj = it.next(result);
        _run();
      }).catch(err => it.throw(err));
    }
  }());
}

// Example of usage
run(function*() {
  try {
    var app = yield getApp(12312);
    var user = yield getUser(23123);
    console.log(app, user);
  } catch(e) {
    console.error(e);
  }
});