2-14、for await .. of 有什么作用

知识点

for await .. of 用于遍历一组 Promise

Promise.all

<script>
    function getPromise(num) {
        return new Promise((resolve, reject) => {
            setTimeout(() => {
                resolve(num);
            }, 1000);
        });
    }

    (async function () {
        const data = [10, 20, 30];
        for (let val of data) {
            const res = await getPromise(val);
            console.log(res);
        }

        // const res1 = await getPromise(data[0])
        // console.log(res1);
        // const res2 = await getPromise(data[1])
        // console.log(res2);
        // const res3 = await getPromise(data[2])
        // console.log(res3);
    })()


    // const p1 = getPromise(10);
    // const p2 = getPromise(20);
    // const p3 = getPromise(30);

    // const list = [p1, p2, p3];

    // (async function () {
    //     for await (let res of list) {
    //         console.log(res);
    //     }
    // })()

    // 会返回数组，数据全在数组里面
    // Promise.all(list).then((res) => {
    //     console.log(res);
    // })