sleep实现

[nianxiongdi]

方式1

async function sleep(delay) {
    return new Promise((resolve, reject)=>{
        setTimeout(function(){}, delay);
        resolve('success delay');
    });
}

const start = Date.now();
(async function(){
    await sleep(2000);
})()
const end = Date.now();

方式2

function sleep(delay){
    const start = Date.now();
    while(Date.now() - start <delay){}
}

sleep(2000);