vue中用async/await 来处理异步

function setTimeFun() {
  return new Promise((resolve, rejects) => {
    setTimeout(() => {
      console.log(3)
      resolve()
    }, 3000)
  })
}
async function testFun() {
  console.log(1)
  await setTimeFun()    
  console.log(2)  // 等输出3秒后输出3才会执行
}
testFun()