Executing promises sequentially

sequentially.js

const times = [ 1, 3, 4, 2 ];

const sleep = ms =>
  new Promise(res => {
    const t = ms * 1000;
    setTimeout(res, t)
  })

const myPromise = num =>
  sleep(num).then(() => {
    console.log('done: ' + num)
  })

times.reduce(
  (p, x) =>
    p.then(_ => myPromise(x)),
    Promise.resolve()
);