### setTimeout实现setInterval ``` var myInterval = function(fn,timeout){ var clearTime = null var interval = function(){ clearTime = setTimeout(()=>{ fn() interval() },timeout) } interval() return ()=>clearTimeout(clearTime); } var cancel = myInterval(()=>{ console.log(123) },1000) setTimeout(()=>{cancel()},10000) // 模拟10000ms后清除定时器 ```