封装代码

    1. function tottle(fn,delay=500){
    2.     let timer= null;
    3.     return function(){
    4.         if(timer){
    5.             return
    6.         }
    7.         timer = setTimeOut(()=>{
    8.             fn.call(this);
    9.             timer = null;
    10.         },delay)
    11.     }
    12. }