asyncAwait.js

/* ------------------------------------------------------------------------- *
        Async / Await simple implementation with generators and promises
* -------------------------------------------------------------------------- */

const wrap = generator => (...args) => {
  const iterator = generator(...args)
  const loop = ({ value: promise, done }) => {
    if (!done) {
      promise.then(
        x => loop(iterator.next(x)),
        x => loop(iterator.throw(x))
      )
    }
  }
  loop(iterator.next())
}


const myAsync = wrap(function* () {
  const res = yield new Promise((res, rej) => setTimeout(() => res(10), 2000))
  
  console.log(res)
  // => 10
  
  const second = yield new Promise((res, rej) => setTimeout(() => res(80), 1200))
  
  console.log(second)
  // => 80
})

myAsync()

/* ----------------------------------------- *
        With Async / Await
* ----------------------------------------- */

const myAsync = async () => {
  const res = await new Promise((res, rej) => setTimeout(() => res(10), 2000))
  
  console.log(res)
  // => 10
  
  const second = await new Promise((res, rej) => setTimeout(() => res(80), 1200))
  
  console.log(second)
  // => 80
}