parallel.ts

import {sleep} from 'previousExample'

async function slowDouble (i): Promise<number> {
  await sleep(1000) // non-blocking
  return 2 * i
}

async function main () {
  // slowDouble is async, therefore it returns a promise
  const result = await Promise.all([1, 2, 3].map(slowDouble))
  console.log(result) 
}

main() // outputs [2, 4, 6] after 1000ms