1.sleep函数
sleep函数作用是让线程休眠，等到指定时间在重新唤起。
2、sleep实现
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<script type="text/javascript">
//方法一
function sleep1(ms, callback) { setTimeout(callback, ms) } //sleep 1s
sleep1(1000, () => { console.log(1000) }) //方法二
function sleep2(ms) { return new Promise(function(resolve, reject) { setTimeout(resolve, ms) }) } sleep2(1000).then(() => { console.log(2000) }) //方法三
function sleep3(ms) { return new Promise(function(resolve, reject) { setTimeout(resolve, ms) }) } async function init() { await sleep3(1000); } init().then(() => { console.log(3000) }) </script>
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