async-await.js

async function sleep(ms) {
  return new Promise(r => setTimeout(r, ms))
}

async function foo() { console.log('s foo'); await sleep(2000); console.log('d foo'); return 'foo'; }
async function bar() { console.log('s bar'); await sleep(1000); console.log('d bar'); return 'bar'; }
async function baz() { console.log('s baz'); await sleep(2000); console.log('d baz'); return 'baz'; }

async function run() {
  console.log('start')
  var a = [foo(), bar(), baz()]
  a.forEach(async (d) => {
    let x = await d
    console.log(x)
  })
  console.log('done')
}

async function run2() {
  console.log('start')
  var a = [foo(), bar(), baz()]
  for (let d of a) {
    let x = await d
    console.log(x)
  }
  console.log('done')
}

async function run3() {
  console.log('start')
  var a = [foo(), bar(), baz()]
  await* a.map(async d => {
    let x = await d
    console.log(x)
  })
  console.log('done')
}

run3()