Simple ES7 async function example: sleep

async-function.js

function sleep(duration) {
  return new Promise(function(resolve, reject) {
    setTimeout(()=> { resolve(0) }, duration);
  })
}

async function delayedMessage(message, delay) {
  let remainingTime = await sleep(delay)
  console.log(message, `(remaining time: ${remainingTime})`)
}

delayedMessage("World", 400).then(()=>{ console.log('done') })
delayedMessage("Hello", 200)

// Output:
// Hello (remaining time: 0)
// World (remaining time: 0)
// done

try-it.md

Try it in Babel