async函数

    <script>
        async function main() {
            //如果返回值是一个非promise函数
            return 521
        }
        let p = main()
        console.log(p);
    </script>

    <script>
        async function main() {
            //如果返回值是一个非promise函数
            return new Promise((resolve,reject)=>{
                reject('FALSE')
            })
        }
        let p = main()
        console.log(p);
    </script>

    <script>
        async function main() {
            throw 'OH,NO'
        }
        let p = main()
        console.log(p);
    </script>