Q.aync and ES6 generators

q_async.js

Q.async(function* () {
  try {
    var value1 = yield step1();
    var value2 = yield step2(value1);
    var value3 = yield step3(value2);
    var value4 = yield step4(value3);
  } catch (e) {
    // Handle any error from step1 through step4
  }
});