1-4 面试题

1-1 promise和定时器

<!--
        知识点:异步
        面试题: promise和定时器执行顺序的问题:
         promise会优先于定时器去执行
    -->
    <script>
        console.log("3");
        setTimeout(() => {
            console.log(2)
        });
        Promise.resolve().then(()=>{
            console.log(1)
        })
    </script>

1-2 await

/* await   阻塞线程  会从异步函数中跳出来,优先执行同步代码 */
        async function show(){
            console.log(1);
            var res = await 100;
            console.log(res);
        }
        show();
        console.log(2);
        setTimeout(() => {
            console.log(3)
        }, 1000);
        /* 
        1
        2
        100
        3
         */