promise.js

const one = (msg) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log('1');
      resolve();
    }, 2000);
  });
}

const sec = () => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log('2');
      resolve();
    }, 1000);
  });
}



Promise.resolve()
  .then(() => {
    return one();
  })
  .then(() => {
    return sec();
  })
  .then(() => {
    process.exit(0);
  });