好玩的.async

版权声明：个人笔记，不喜勿喷 https://blog.csdn.net/qq_39571197/article/details/88996699

如果没有await，asycn function其实是同步的！

    // 同步
    let count = 0;
    async function fn(index = 0) {
        count++;
        if (index === 5) {
            return Date.now();
        }
        // await new Promise(resolve => {
        //     setTimeout(resolve, 1000);
        // });
        return fn(++index);
    }
    fn().then(function () {
        console.log(count);
    });
    console.log(count);

    // 异步
    let count = 0;
    async function fn(index = 0) {
        count++;
        if (index === 5) {
            return Date.now();
        }
        await new Promise(resolve => {
            setTimeout(resolve, 1000);
        });
        return fn(++index);
    }
    fn().then(function () {
        console.log(count);
    });
    console.log(count);