async&await 并行/串行優化

async&await.js

function getData() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(1)
    },2000)
  })
}

async function get() {
  return await getData()
}

// console.log(Object.prototype.toString.call(get()));

(async function init() {
  const start = console.time()

  // 1：
  // const a = await getData()
  // const b = await getData()

  // 2：
  const [a,b] = await Promise.all([getData(),getData()])

  // 3.
  // const aP = getData()
  // const bP = getData()

  const end = console.timeEnd();

  console.log(start - end);

  console.log(a+b);
  
  // console.log('>>>>>>>',(await aP) + (await bP));
})()