1. async function test1() {
    2.     console.log('test1 begin');
    3.   const result = await test2();
    4.   console.log('result', result);
    5.   console.log('test1 end');              
    6. }
    8. async function test2(){ // 异步函数默认返回一个 Promise
    9.     console.log('test2');
    10.   return Promise.reslove('haha')
    11. }
    13. console.log('script begin');
    14. test1();
    15. console.log('script end');

    输出

    1. script begin
    2. test1 begin
    3. test2
    4. script end
    5. result haha
    6. test1 end

    可以把 await后面的代码当成一个 setTimeout(()=>{}) 包裹住（是异步）, 以便理解