Example of async requests in series

requestsInSeries.js

const sleep = s =>
  new Promise(resolve =>
    setTimeout(resolve, s * 1000))

const fetch = url =>
  new Promise(resolve =>
    setTimeout(() => resolve(url), 1.5 * 1000))

// Promise.all([
//   'a',
//   'b',
//   sleep(2),
// ]).then(result => {
//     console.log(result)
// })

fetch('first url')
  .then((result) => {
    console.log(result, '<= first finished with this url')
    return fetch('second url')
  })
  .then(async (resultOf2ndFetch) => {
    console.log('result of 2nd fetch: ', resultOf2ndFetch)
    console.log('hey i wait here: =====')

    await sleep(2)

    console.log(' hey i finished waiting here :)')
    return fetch('last url is here' + resultOf2ndFetch)
  })
  .then(result => {
    console.log('6 seconds passed, and heres result', result)
  })