// 防抖 定时器
let timer;
//list就是电影列表 ref="list" $el获取DOM元素
this.$refs.list.$el.addEventListener("scroll", e => {
 console.log("---->",e.target.scrollTop) //不使用防抖
 if (timer) {
 //清空timer
 clearTimeout(timer);
 }
 timer = setTimeout(() => {
 console.log(e.target.scrollTop) //使用防抖
 
 //在sessionStorage中保存当前下拉位置
 // sessionStorage.setItem("position", e.target.scrollTop);
 }, 75); //75mm为最佳
});

<template>
 <div>
  <input type="text" @keyup="debounce" />
 </div>
</template>

<script>
//定义 timer
let timer;
export default {
 methods: {
  debounce: function() {
   if (timer) {
    clearTimeout(timer);
   }
   timer = setTimeout(() => {
    console.log("防抖...");
    timer = undefined;
   }, 2000);
  }
 }
};
</script>

<template>
 <div>
  <button @click="throttle">按钮</button>
 </div>
</template>

<script>
//定义
let timer, lastTime;
export default {
 methods: {
  throttle: function() {
   let now = +new Date();
   if (lastTime && lastTime - now < 200) { //在200ms内点击多次，只有一次生效
    clearTimeout(timer);
   }
   timer = setTimeout(() => {
    console.log("点击...");
    lastTime = +new Date();
   }, 200);
  }
 }
};
</script>

/**
 * 函数防抖 (只执行最后一次点击)
 */
export const Debounce = (fn, t) => {
  let delay = t || 500;
  let timer;
  console.log(fn)
  console.log(typeof fn)
  return function () {
    let args = arguments;
    if(timer){
      clearTimeout(timer);
    }
    timer = setTimeout(() => {
      timer = null;
      fn.apply(this, args);
    }, delay);
  }
};
/*
 * 函数节流
 */
export const Throttle = (fn, t) => {
  let last;
  let timer;
  let interval = t || 500;
  return function () {
    let args = arguments;
    let now = +new Date();
    if (last && now - last < interval) {
      clearTimeout(timer);
      timer = setTimeout(() => {
        last = now;
        fn.apply(this, args);
      }, interval);
    } else {
      last = now;
      fn.apply(this, args);
    }
  }
};