async await promise 定时器效果，每隔一秒输出数组中的数字

async await promise 定时器效果，每隔一秒输出数组中的数字

 let arr = [1,2,3,4]
    async function sleep() {
        return new Promise(resolve => {
            setTimeout(() => {
                resolve()
            }, 1000)
        })
    }
    (async () => {
        for(let i in arr){
            await sleep ();
            console.log(arr[i]);
        }
    })()