function wait(milliseconds) {
  return new Promise(resolve => {
    setTimeout(resolve, milliseconds);
  });
}

const hi = async delay => {
  await wait(delay);
  console.log("hi");
};

const bye = async () => {
  await hi(1000);
  await hi(1000);
  await hi(1000);
  await hi(1000);
  return 'bye';
};

bye().then(msg => {
  console.log(msg);
});