函数的节流和防抖

防抖函数：将多次触发变成最后一次触发


function debounce(fn,wait){
  let timer = null;
  return function (){
    let arg = arguments;
    if(timer){
      clearTimeout(timer);
      timer = null;
    }
    timer = setTimeout(()=>{
       fn.apply(this,arg)
    },wait)
  }
}
function clg(){
  console.log('clg')
}
window.addEventListener('resize',debounce(clg,1000))

节流函数：将多次执行变成每隔一个时间节点去执行的函数

function throttle(fn,time){
  let lastTime = null;
  return function(){
    let nowTime = Date.now();
    if(nowTime - lastTime > time || !lastTime){
      fn();
      last = nowTime
    }
  }
}
function sayHi(){
  console.log('hi')
}
setInterval(throttle(sayHi,1000),500)