Vue implements the component that returns the top backToTop

export function scrollIt(

 destination = 0,

 duration = 200,

 easing = "linear",

 callback

) {

 // define timing functions -- 过渡动效

 let easings = {

  // no easing, no acceleration

  linear(t) {

   return t;

  },

  // accelerating from zero velocity

  easeInQuad(t) {

   return t * t;

  },

  // decelerating to zero velocity

  easeOutQuad(t) {

   return t * (2 - t);

  },

  // acceleration until halfway, then deceleration

  easeInOutQuad(t) {

   return t < 0.5 ? 2 * t * t : -1 + (4 - 2 * t) * t;

  },

  // accelerating from zero velocity

  easeInCubic(t) {

   return t * t * t;

  },

  // decelerating to zero velocity

  easeOutCubic(t) {

   return --t * t * t + 1;

  },

  // acceleration until halfway, then deceleration

  easeInOutCubic(t) {

   return t < 0.5 ? 4 * t * t * t : (t - 1) * (2 * t - 2) * (2 * t - 2) + 1;

  },

  // accelerating from zero velocity

  easeInQuart(t) {

   return t * t * t * t;

  },

  // decelerating to zero velocity

  easeOutQuart(t) {

   return 1 - --t * t * t * t;

  },

  // acceleration until halfway, then deceleration

  easeInOutQuart(t) {

   return t < 0.5 ? 8 * t * t * t * t : 1 - 8 * --t * t * t * t;

  },

  // accelerating from zero velocity

  easeInQuint(t) {

   return t * t * t * t * t;

  },

  // decelerating to zero velocity

  easeOutQuint(t) {

   return 1 + --t * t * t * t * t;

  },

  // acceleration until halfway, then deceleration

  easeInOutQuint(t) {

   return t < 0.5 ? 16 * t * t * t * t * t : 1 + 16 * --t * t * t * t * t;

  }

 };

 // requestAnimationFrame()的兼容性封装：先判断是否原生支持各种带前缀的

 //不行的话就采用延时的方案

 (function() {

  var lastTime = 0;

  var vendors = ["ms", "moz", "webkit", "o"];

  for (var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {

   window.requestAnimationFrame =

    window[vendors[x] + "RequestAnimationFrame"];

   window.cancelAnimationFrame =

    window[vendors[x] + "CancelAnimationFrame"] ||

    window[vendors[x] + "CancelRequestAnimationFrame"];

  }

  if (!window.requestAnimationFrame)

   window.requestAnimationFrame = function(callback, element) {

    var currTime = new Date().getTime();

    var timeToCall = Math.max(0, 16 - (currTime - lastTime));

    var id = window.setTimeout(function() {

     callback(currTime + timeToCall);

    }, timeToCall);

    lastTime = currTime + timeToCall;

    return id;

   };

  if (!window.cancelAnimationFrame)

   window.cancelAnimationFrame = function(id) {

    clearTimeout(id);

   };

 })();

 function checkElement() {

  // chrome,safari及一些浏览器对于documentElemnt的计算标准化,reset的作用

  document.documentElement.scrollTop += 1;

  let elm =

   document.documentElement.scrollTop !== 0

    ? document.documentElement

    : document.body;

  document.documentElement.scrollTop -= 1;

  return elm;

 }

 let element = checkElement();

 let start = element.scrollTop; // 当前滚动距离

 let startTime = Date.now(); // 当前时间

 function scroll() { // 滚动的实现

  let now = Date.now();

  let time = Math.min(1, (now - startTime) / duration);

  let timeFunction = easings[easing](time);

  element.scrollTop = timeFunction * (destination - start) + start;

  if (element.scrollTop === destination) {

   callback; // 此次执行回调函数

   return;

  }

  window.requestAnimationFrame(scroll);

 }

 scroll();

}

<template>

 <p class="back-to-top" @click="backToTop" v-show="showReturnToTop" @mouseenter="show" @mouseleave="hide">

  <i :class="[bttOption.iClass]" :style="{color:bttOption.iColor,&#39;font-size&#39;:bttOption.iFontsize}"></i>

  <span class="tips" :class="[bttOption.iPos]" :style="{color:bttOption.textColor}" v-show="showTooltips">{{bttOption.text}}</span>

 </p>

</template>

<script>

 import { scrollIt } from './scrollIt'; // 引入动画过渡的实现

 export default {

  name: 'back-to-top',

  props: {

   text: { // 文本提示

    type: String,

    default: '返回顶部'

   },

   textColor: { // 文本颜色

    type: String,

    default: '#f00'

   },

   iPos: { // 文本位置

    type: String,

    default: 'right'

   },

   iClass: { // 图标形状

    type: String,

    default: 'fzicon fz-ad-fanhuidingbu1'

   },

   iColor: { // 图标颜色

    type: String,

    default: '#f00'

   },

   iFontsize: { // 图标大小

    type: String,

    default: '32px'

   },

   pageY: { // 默认在哪个视图显示返回按钮

    type: Number,

    default: 400

   },

   transitionName: { // 过渡动画名称

    type: String,

    default: 'linear'

   }

  },

  data: function () {

   return {

    showTooltips: false,

    showReturnToTop: false

   }

  },

  computed: {

   bttOption () {

    return {

     text: this.text,

     textColor: this.textColor,

     iPos: this.iPos,

     iClass: this.iClass,

     iColor: this.iColor,

     iFontsize: this.iFontsize

    }

   }

  },

  methods: {

   show () { // 显示隐藏提示文字

    return this.showTooltips = true;

   },

   hide () {

    return this.showTooltips = false;

   },

   currentPageYOffset () {

    // 判断滚动区域大于多少的时候显示返回顶部的按钮

    window.pageYOffset > this.pageY ? this.showReturnToTop = true : this.showReturnToTop = false;

   },

   backToTop () {

    scrollIt(0, 1500, this.transitionName, this.currentPageYOffset);

   }

  },

  created () {

   window.addEventListener('scroll', this.currentPageYOffset);

  },

  beforeDestroy () {

   window.removeEventListener('scroll', this.currentPageYOffset)

  }

 }

</script>

<style scoped lang="scss">

 .back-to-top {

  position: fixed;

  bottom: 5%;

  right: 100px;

  z-index: 9999;

  cursor: pointer;

  width: auto;

  i {

   font-size: 32px;

   display: inline-block;

   position: relative;

   text-align: center;

   padding: 5px;

   background-color: rgba(234, 231, 231, 0.52);

   border-radius: 5px;

   transition: all 0.3s linear;

   &:hover {

    border-radius: 50%;

    background: #222;

    color: #fff !important;

   }

  }

  .tips {

   display: inline-block;

   position: absolute;

   word-break: normal;

   white-space: nowrap;

   width: auto;

   font-size: 12px;

   color: #fff;

   z-index: -1;

  }

  .left {

   right: 0;

   top: 50%;

   margin-right: 50px;

   transform: translateY(-50%);

  }

  .right {

   left: 0;

   top: 50%;

   margin-left: 50px;

   transform: translateY(-50%);

  }

  .bottom {

   bottom: 0;

   margin-top: 50px;

  }

  .top {

   top: 0;

   margin-bottom: 50px;

  }

 }

</style>