SOURCE

let num = 1
let box = document.querySelector('#app')
box.innerText = num
function userAction(e,b){
  console.log(e)
  console.log(b)
  box.innerText = num++
}
let userActionFn = throttle(userAction,1000,true)
box.onmousemove = function(e){
  userActionFn(e,'bbbbb')
}
// 防抖函数
function debounce(fn, wait,im) {
  let timer = null
  return function() {
    if(timer) clearTimeout(timer)
    if(im){
      let callNow = !timer
      timer = setTimeout(()=>{
        timer = null
        fn.apply(this,arguments)
      },wait)
      if(callNow) fn.apply(this,arguments)
    }else {
       timer = setTimeout(()=>{
      fn.apply(this,arguments)
    }, wait)
    }
   
  }
}

// 截流函数
function throttle(fn,wait){
  let timeout = null
  let previous = 0,remain = 0;
  // return function(){
  //   if(!timeout){
  //     timeout = setTimeout(()=>{
  //       fn.apply(this,arguments)
  //       timeout = null
  //     },wait)
  //   }
  // }
  // return function(){
  //   let now = new Date().getTime();
  //   if(now - previous>=wait){
  //     fn.apply(this,arguments)
  //     previous = now
  //   }
  // }
  let throttled = function(){
    let now = new Date().getTime()
    let remain = wait -(now-previous)
    if(remain<=0){
      if(timeout){
        clearTimeout(timeout)
        timeout = null
      }out
      previous = now
      fn.apply(this,arguments)
    }else if(!timeout) {
      timeout = setTimeout(()=>{
        fn.apply(this,arguments)
        previous = new Date().getTime()
        timeout = null
      },remain)
    }
  }
  return throttled
}

<div id="app">
</div>

html,
body {
  height: 100%;
  width: 100%;
}

#app {
  height: 100%;
  width: 100%;
  background: #666;
  color: #fff
}