sleep函数

异步的sleep

function sleep(wait) {
    return new Promise(resolve => {
        setTimeout(() => {
            resolve()
        }, wait);
    })
}

测试

sleep(2000).then(res=>{
    console.log('foo');
})

同步阻塞的sleep

function sleep(wait) {
    let now = Date.now()
    let overTime = now + wait
    while (true) {
        if (overTime < now) break
        now = Date.now()
    }
}

测试

sleep(2000)
console.log('foo');