复习之async

  function aa() {
            return new Promise((resolve, reject) => {
                setTimeout(() => {
                    const num = parseInt(Math.random() * 100);
                    if (num % 2) {
                        resolve(num)
                    } else {
                        reject(num)
                    }
                }, 1000)
            })
        }



        async function fn() {
            // await 等待  
            let res = await aa();
            console.log(res);  //promise
            return res
        }

        const result = fn();
        console.log(result);  //成功的结果