ES7 async/await

ES7 async/await

async/await 是ES7引入的新語法，能夠更加方便的進行異步操做
async 關鍵字用於函數上(async函數的返回值是Promise實例對象)
await 關鍵字用於async函數當中(await能夠獲得異步的結果)

async function queryData (id) {
  const res = await axios.get('/data')
  return res.data
}
queryData.then(data => {
  console.log(data)
})

async/await 處理多個異步請求

async function queryData () {
  const info = await axios.get('/async1')
  const res = await axios.get('async2?info=' + info.data)
  return res
}

queryData.then(res => {
  console.log(res)
})