run.js

// https://twitter.com/antonybudianto/status/1387211508296261633
async function serialCon(fns, limit) {
  const queue = [...fns]
  const workers = []

  for (let i = 0; i < limit; i += 1) {
    workers.push((async () => {
      while (queue.length > 0) {
        const fn = queue.shift()
        await fn()
      }
    })())
  }

  await Promise.all(workers)
}

const wait = ms => new Promise(resolve => setTimeout(resolve, ms))

serialCon(
  [5000, 100, 200, 300, 400, 500].map(ms => async () => {
    await wait(ms)
    console.log(ms)
  }),
  1
).catch(console.error)