Comment le framework UI de vue implémente-t-il le chargement glissant des données ?

<p ref="scroll" class="r-scroll">
 <p class="r-scroll-wrap">
  <slot></slot>
 </p>
 <slot name="loading">
  <p v-show="isLoading" class="r-scroll-loading">
   <r-loading></r-loading>
   <span class="r-scroll-loading-text">{{loadingText}}</span>
  </p>
 </slot>
 <slot name="complate">
  <p v-show="isComplate" class="r-scroll-loading">{{complateText}}</p>
 </slot>
</p>

<style lang="scss">
@mixin one-screen {
 position: absolute;
 left:0;
 top:0;
 width:100%;
 height:100%;
 overflow: hidden;
}
@mixin overflow-scroll {
 overflow: scroll;
 -webkit-overflow-scrolling: touch;
}

.r-scroll{
 @include one-screen;
 @include overflow-scroll;
 &-loading{
  text-align: center;
  padding-top: 3vw;
  padding-bottom: 3vw;
  font-size: 14px;
  color: #656565;
  line-height: 20px;
  &-text{
   display: inline-block;
   vertical-align: middle;
  }
 }
}
</style>

<script>
import rLoading from &#39;../loading&#39;
export default{
 components: {rLoading},
 props: {
  // 距离底部数值，小于或等于该数值触发自定义事件loadmore
  bottomDistance: {
   type: [Number, String],
   default: 70
  },
  // 加载中的文字
  loadingText: {
   type: String,
   default: &#39;加载中...&#39;
  },
  // 数据加载完成的文字
  complateText: {
   type: String,
   default: &#39;-- 我是个有底线的列表 --&#39;
  }
 },
 data () {
  return {
   // 用来判定数据是否加载完成
   isComplate: false,
   // 用来判定是否正在加载数据
   isLoading: false,
   // 组件容器
   scroll: null,
   // 正文容器
   scrollWrap: null
  }
 },
 watch: {
  // 监听isLoading，如果isLoading的值为true则代表触发了loadmore事件
  isLoading (val) {
   if (val) {
    this.$emit(&#39;loadmore&#39;)
   }
  }
 },
 methods: {
  // 初始化组件，获取组件容器、正文容器节点，并给组件容器节点绑定滚动事件
  init () {
   this.scroll = this.$refs.scroll
   this.scrollWrap = this.scroll.childNodes[0]
   this.scroll.addEventListener(&#39;scroll&#39;, this.scrollEvent)
   this.$emit(&#39;init&#39;, this.scroll)
  },
  scrollEvent (e) {
   // 如果数据全部加载完成了，则再也不触发loadmore事件
   if (this.isComplate) return
   let scrollTop = this.scroll.scrollTop
   let scrollH = this.scroll.offsetHeight
   let scrollWrapH = this.scrollWrap.offsetHeight
   // 组件容器滚的距离 + 组件容器本身距离大于或者等于正文容器高度 - 指定数值 则触发loadmore事件
   if (scrollTop + scrollH >= scrollWrapH - this.bottomDistance) {
    this.isLoading = true
   }
  },
  // 当前数据加载完成后调用该函数
  loaded () {
   this.isLoading = false
  },
  // 所有数据加载完成后调用该函数
  compleate () {
   this.isLoading = false
   this.isComplate = true
   this.scroll.removeEventListener(&#39;scroll&#39;, this.scrollEvent)
  }
 },
 mounted () {
  this.$nextTick(this.init)
 }
}
</script>

<template>
 <p class="r-loading-container">
  <img src="./loading.gif">
 </p>
</template>
<script>
export default {}
</script>
<style lang="scss">
.r-loading-container{
 display: inline-block;
 vertical-align: middle;
 img{
  width: 20px;
  height: 20px;
  display: block;
 }
}
</style>

<template>
 <p class="index">
  <r-scroll ref="scroll" @loadmore="queryDate">
   <p class="item" v-for="(item, index) in list">{{item}}</p>
  </r-scroll>
 </p>
</template>

<script>
import rScroll from &#39;../../components/scroll&#39;
function timeout (ms) {
 return new Promise((resolve, reject) => {
  setTimeout(resolve, ms, &#39;done&#39;)
 })
}

export default{
 components: {rScroll},
 data () {
  return {
   i: 0,
   list: []
  }
 },
 methods: {
  async queryDate () {
   await timeout(1000)
   let i = this.i
   let data = []
   for (let j = 0; j < 40; j++) {
    data.push(i + j)
    this.i = this.i + 1
   }
   this.list = this.list.concat(data)
   // 调用组件中的loaded函数，如果数据加载完成后记得调用组件的compleate函数
   this.$refs.scroll.loaded()
  }
 },
 mounted () {
  this.queryDate()
 }
}
</script>

<style lang="scss">
.item{
 background-color: #f2f2f2;
 border-bottom: 1px solid #fff;
 height: 40px;
 line-height: 40px;
 text-align: center;
}
</style>