Vue 虚拟列表的实战示例

目录

• 序言
• 设计
• 实现
• 小结

<template>
 <div class="endless-scrolling-list">
  <!-- 搜索框 -->
  <div class="search-box">
   <input type="text" v-model="searchQuery"/>
  </div>
  <p class="center" v-if="results.length == 0 && !loading">
   Start typing to search something.
  </p>
  <!-- 虚拟列表 -->
  <virtual-list
   :data-key="'pageid'"
   :data-sources="results"
   :data-component="itemComponent"
   :page-mode="true"
   />
  <!-- loading -->
  <loader v-if="loading" />
 </div>
</template>

import axios from 'axios';
import lodash from 'lodash';
import VirtualList from 'vue-virtual-scroll-list';
import SearchResult from './SearchResult';
import Loader from './Loader';
export default {
 name: 'EndlessList',
 components: {
  VirtualList,
  Loader
 },
 data() {
  return {
   searchQuery: '',
   currentPage: 0,
   results: [],
   itemComponent: SearchResult,
   loading: false
  }
 },
};

<template>
 <div class="list-item">
  <h3>
   {{ source.title }}
  </h3>
  <div v-html="source.snippet"></div>
 </div>
</template>
<script>
export default {
 props: {
  index: {
   // index of current item
   type: Number,
  },
  source: {
   type: Object,
   default() {
    return {};
   },
  },
 },
};
</script>
<style scoped>
.list-item {
 padding: 0 10px 20px 10px;
}
.list-item h3 {
 margin: 0;
 padding-bottom: 10px;
}
</style>

search(query, page) {
 // We prepare the data that the Wikipedia API expects.
 const data = {
  action: "query",
  format: "json",
  list: "search",
  continue: "-||",
  utf8: 1,
  srsearch: query,
  sroffset: page * 10,
  origin: "*",
 };
 // And then we convert these params TO GET params in the format
 // action=query&format=json ...
 const params = Object.keys(data)
  .map(function(k) {
   return data[k] == ""
    ? ""
    : encodeURIComponent(k) + "=" + encodeURIComponent(data[k]);
  })
  .join("&");
 // We prepare the url with the params string
 const searchUrl = `https://en.wikipedia.org/w/api.php?${params}`;
 // we set loading to true so that we can display the loader 
 this.loading = true;
 // Then we execute the request and concatenate the results
 axios.get(searchUrl).then((response) => {
  this.results = this.results.concat(response.data.query.search);
  // And of course set loading to false to hide the loader.
  this.loading = false;
 });
}

<script>
export default {
 // data() and methods skipped for brevity
 watch: {
  searchQuery: {
   immediate: true,
   handler: lodash.debounce(function (newVal) {
    if (newVal == "") {
     return;
    }
    this.results = [];
    this.currentPage = 0;
    this.search(newVal, this.currentPage);
    this.search(newVal, this.currentPage + 1);
    this.currentPage = 2;
   }, 200),
  },
 },
 mounted() {
  const vm = this;
  window.onscroll = lodash.debounce(function () {
   var distanceFromBottom =
    document.body.scrollHeight - window.innerHeight - window.scrollY;
   if (distanceFromBottom < 400 && vm.searchQuery !== "") {
    vm.search(vm.searchQuery, vm.currentPage);
    vm.currentPage++;
   }
  }, 100, {leading: true});
 },
}
</script>

npm run dev