Serialize promise calls (run promises sequentially)

serialize.js

// promise
const sleep = (timeout, v) => new Promise(r => setTimeout(() => r(v), timeout));
// series to call
const series = [() => sleep(1000, 1), () => sleep(1000, 2), () => sleep(1000, 3)];

// serialize
const r = series
  .reduce(
    (m, p) => m.then(v => Promise.all([...v, p()])),
    Promise.resolve([])
  );

// get result
r.then((r) => console.log('done', r))
// out [1, 2, 3]