//大家可以看看这个执行顺序,都知道是1,2,3asyncfunctiontest(){
a =1await console.log(1)
b =2await console.log(2)
c =3await console.log(3)return4}//原理functiontest(){return Promise.resolve().then(()=>{
a=1return console.log(1)//return返回的也是promise}).then(()=>{
c=2return console.log(2)}).then(()=>{
c =3return console.log(3)}).then(()=>{return4})}