vue 之组件递归；

在开发一个 PC 端的项目时，需要开发一个树状结构，直接上效果图如下：点击 "+" 号的时候则展开下一级，点击 "-" 号的时候则收起；

之所以写这篇博客，因为在实现过程中用到了组件递归，觉得之后再遇到此种功能时能借鉴一下，treeViewItem.vue 中通过 name： "treeViewItem" 实现组件内自己调用自己，实现组件递归，从而实现对树状结构数据的渲染；

数据结构如下：

代码如下：

menusModule.js （store/module/menusModule.js）

let menus = [];
let levelNum = 1;
let currentComCode = '';
let startExpand = []; // 保存刷新后当前要展开的菜单项
if(localStorage.getItem('comInfoParam')){
  currentComCode = JSON.parse(localStorage.getItem('comInfoParam')).key;
}
function setExpand(source, url) {
  let sourceItem = '';
  for (let i = 0; i < source.length; i++) {
    sourceItem = JSON.stringify(source[i]); // 把菜单项转为字符串
    if (sourceItem.indexOf(url) > -1) { // 查找当前 URL 所对应的子菜单属于哪一个祖先菜单
      if (source[i].type === 'button') { // 导航菜单为按钮
        source[i].isSelected = true; // 设置选中高亮
        source[i].isExpanded = true; // 设置为展开
        startExpand.push(source[i]);
        // 递归下一级菜单，以此类推
        setExpand(source[i].subMenu, url);
      }
      break;
    }
  }
}
const state = {
  menus,
  levelNum,
  currentComCode
};
const mutations = {
  findParents(state, payload) {
    if (payload.menu.ifExits === 'true') {
      payload.menu.isExpanded = !payload.menu.isExpanded;
    } else if (payload.menu.ifExits === 'false') {
      if (startExpand.length > 0) {
        for (let i = 0; i < startExpand.length; i++) {
          startExpand[i].isSelected = false;
        }
      }
      startExpand = []; // 清空展开菜单记录项
      setExpand(state.menus, payload.menu.url);
    };
  },
  firstInit(state, payload) {
    setExpand(state.menus, payload.url);
  },
  getList(state, payload) {
    state.menus = payload;
  },
  getCurrentComCode(state,payload) {
    state.currentComCode = payload;
  }
}
export default {
  state,
  mutations
};

index.js （store/index.js）

import Vue from 'vue'
import Vuex from 'vuex'
import menusModule from './module/menusModule'
Vue.use(Vuex);
const store = new Vuex.Store({
  modules: {
    menusModule
  }
})
export default store

categoryManage.vue

<template>
  <main class='categoryManage'>
    <h2>类目管理</h2>
    <div class="categoryContent">
      <div class="operateCategory">
        <button @click="addNewCategory">添加类目</button>
      </div>
      <div class="categoryTab">
        <div class="categoryTabHeader">
          <div class="categoryCode">类目编码</div>
          <div class="col-1 categoryName">类目名称</div>
          <div class="col-2 isDisplay">是否展示</div>
          <div class="col-3 categoryGrade">类目等级</div>
          <div class="col-4 categoryOperate">操作</div>
        </div>
        <div class="categoryTabBody">
          <tree-view></tree-view>
        </div>
        <!-- 查询数据为空时 -->
        <div class="emptyTab" v-if='categoryList.length === 0'>
          <span>啊噢~~ 查询不到数据,您可以点击右上角按钮手动添加类目.</span>
        </div>
      </div>
    </div>
    <hd-diolag :is-show="isShowDiolag" @getdata="isShowDiolag=false">
      <p>{{contentText}}</p>
    </hd-diolag>
  </main>
</template>
<script>
import treeView from './treeView.vue';
import { getCategoryList } from '../../../api/commodityDefine/categoryManage.js';

export default {
  data() {
    return {
      categoryList:[],
      isShowDiolag:false,
      contentText:''
    };
  },
  mounted() {
    this.getCategoryListFn();
  },
  methods: {
    getCategoryListFn() {
      let _this = this;
      getCategoryList().then(res => {
        if(res.code === 200){
          _this.categoryList = res.data;
          this.$store.commit("getList", _this.categoryList);
        }else{
          this.isShowDiolag = true;
          this.contentText = res.msg;
        }
      })
    },
    addNewCategory() {
      let _this = this;
      _this.$router.push({
        name: 'newCategory',
        params: {editInfo:null,higherCategory:'',isAddNewFlag:true,categoryList:_this.categoryList}
      });
    },
  },
  components: {
    treeView
  }
};
</script>

<style scoped>
/* 操作区域 */
.categoryManage > h2 {
  height: 60px;
  line-height: 60px;
}
.operateCategory {
  display: flex;
  justify-content: flex-end;
}
.operateCategory > button {
  background: rgb(45, 107, 145);
  border: 1px solid #ddd;
  width: 110px;
  border-radius: 5px;
  color: #fff;
  font-size: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.operateCategory > button:hover {
  background: #39f;
}
.operateCategory > button:before {
  content: '+';
  font-size: 30px;
}
/* 内容展示区域 */
.categoryTab {
  margin-top: 20px;
}
.categoryTab,
.categoryTab .tabRow {
  font-size: 0;
}
.categoryTab .tabRow > div,
.categoryTab .categoryTabHeader > div {
  display: inline-block;
}
.categoryTab .categoryTabHeader > div,
.categoryTab .tabRow > div {
  display: inline-block;
  border-right: 1px solid #ccc;
  border-top: 1px solid #ccc;
  text-align: center;
  box-sizing: border-box;
}
.categoryTab > div.categoryTabHeader > div {
  font-size: 16px;
}
.categoryTab .tabRow > div {
  font-size: 14px;
}
.categoryTab .categoryCode{
  width:17.13%;
}
.categoryTab .col-1 {
  width: 31.47%;
  border-left: 1px solid #ccc;
  position: relative;
}
.categoryTab > div .col-1 > span > span {
  cursor: pointer;
  position: absolute;
  left: 44%;
  font-size: 20px;
  top: -2px;
  font-weight: bold;
}
.categoryTab > div .col-1 > span > span:hover {
  color: #39f;
}
.categoryTab > div .col-2,
.categoryTab > div .col-3,
.categoryTab > div .col-4 {
  width: 17.13%;
}
.categoryTab .tabRow:last-child {
  border-bottom: 1px solid #ccc;
}
.categoryTab .categoryTabHeader {
  height: 32px;
  line-height: 32px;
  color: #fff;
  border-top-left-radius: 5px;
}
.categoryTab .categoryTabHeader > div {
  color: #fff;
  background: #444;
}
.categoryTab .tabRow > div {
  height: 30px;
  line-height: 30px;
}
.categoryOperate > span {
  cursor: pointer;
}
.categoryOperate > span:hover {
  color: #39f;
}
.categoryTab > div .col-1 > span > span.unfoldBtn {
  z-index: 10;
  background: #fff;
  text-align: center;
  width: 1rem;
  top: 0px;
}
/* 无数据时css start */
.emptyTab {
  font-size: 16px;
  height: 500px;
  display: flex;
  align-items: center;
  color: #999;
  justify-content: center;
  border: 1px solid #ccc;
  border-top:none;
}
</style>

treeView.vue

<template>
  <div class="tree-view-menu">
    <tree-view-item :menus='menus'></tree-view-item>
  </div>
</template>
<script>
import treeViewItem from "./treeViewItem";
const menusData = [];
export default {
  components: {
    treeViewItem
  },
  name: "treeViewMenu",
  data() {
    return {
      menus: []
    };
  },
  mounted(){
    let _this = this;
    setTimeout(()=>{
      _this.menus  = _this.$store.state.menusModule.menus;
      for(var i=0;i<_this.menus.length;i++){
        _this.$set(_this.menus[i],'isExpanded',false);
        _this.$set(_this.menus[i],'isSelected',false);
        let childs = _this.menus[i].childs;
        if(childs.length){
          for(var j=0;j<childs.length;j++){
            _this.$set(childs[j],'isExpanded',false);
            _this.$set(childs[j],'isSelected',false);
          }
        }
      }
    },100)
  }
};
</script>
<style scoped>
.tree-view-menu {
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
}
.tree-view-menu::-webkit-scrollbar {
  height: 6px;
  width: 6px;
}
.tree-view-menu::-webkit-scrollbar-trac {
  -webkit-box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.3);
  box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.3);
}
.tree-view-menu::-webkit-scrollbar-thumb {
  background-color: #6e6e6e;
  outline: 1px solid #333;
}
.tree-view-menu::-webkit-scrollbar {
  height: 4px;
  width: 4px;
}
.tree-view-menu::-webkit-scrollbar-track {
  -webkit-box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.3);
  box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.3);
}
.tree-view-menu::-webkit-scrollbar-thumb {
  background-color: #6e6e6e;
  outline: 1px solid #708090;
}
</style>

treeViewItem.vue

<template>
  <div class="tree-view-item">
    <div class="level" :class="'level-'+ menu.gradeNo" v-for="(menu,index) in menus" :key="index">
      <div>
        <div class='itemCode'>
            {{menu.id}}
        </div>

        <div class="button heading name col-1" :class="{selected: menu.isSelected,expand:menu.isExpanded}" @click="toggle(menu)">
          <!-- 折叠展开样式的控制 -->
          <span v-if='menu.childs.length && !menu.isExpanded' :class="{'unfold':menu.childs.length && !menu.isExpanded}">+</span>
          <span v-if='!menu.childs.length || menu.isExpanded' :class="{'fold':!menu.childs.length || menu.isExpanded}">-</span>

          <span>{{menu.name}}</span>
        </div>
        <div class="statusShow col-2">{{statusShowList[menu.ifShow]}}</div>
        <div class="gradeShow col-3">{{categoryList[menu.gradeNo]}}</div>
        <div class="operate col-4">
          <span @click='editCategory(menu)'>编辑</span>
          <!-- 此版本暂不做删除功能 -->
          <!-- <span>|</span>
          <span @click='deleteCategory(menu.gradeNo,index)'>删除</span> -->
        </div>
        <transition name="fade">
          <div class="heading-children" v-show="menu.isExpanded" v-if="menu.childs">
            <tree-view-item :menus='menu.childs' :name='menu.name'></tree-view-item>
          </div>
        </transition>
      </div>
    </div>
  </div>
</template>
<script>
export default {
  name: "treeViewItem",
  props: ["menus","name"],
  data() {
    return {
      categoryList:['','一级类目','二级类目','三级类目','四级类目'],
      statusShowList:['否','是']
    }
  },
  created() {
    this.$store.commit("firstInit", { url: this.$route.path });
  },
  methods: {
    toggle(menu) {
      this.$store.commit("findParents", { menu });
    },
    editCategory(editItem){
      var _this = this;
      this.$router.push({
        name:'newCategory',
        params:{editInfo:editItem,higherCategory:_this.name}
      })
    },
    deleteCategory(level,index){
      this.menus.splice(index,1);
    }
  }
};
</script>
<style scoped>
a {
  text-decoration: none;
  color: #333;
}
.button {
  position: relative;
}
.level-3:hover,
.link:hover,
.button:hover {
  color: #1976d2;
  background-color: #eee;
  cursor: pointer;
}
.icon {
  position: absolute;
  right: 0;
  display: inline-block;
  height: 24px;
  width: 24px;
  fill: currentColor;
  transition: -webkit-transform 0.15s;
  transition: transform 0.15s;
  transition: transform 0.15s, -webkit-transform 0.15s;
  transition-timing-function: ease-in-out;
}
.heading-children {
  padding-left: 14px;
  overflow: hidden;
}
.expand {
  display: block;
}
.collapsed {
  display: none;
}
.expand .icon {
  -webkit-transform: rotate(90deg);
  transform: rotate(90deg);
}
.selected {
  color: #1976d2;
}
.fade-enter-active {
  transition: all 0.5s ease 0s;
}
.fade-enter {
  opacity: 0;
}
.fade-enter-to {
  opacity: 1;
}
.fade-leave-to {
  height: 0;
}

/* 表格css start */
.tree-view-item .name>span:nth-child(1){
  display: inline-block;
  font-size:20px;
  margin-top:-4px;
}
.tree-view-item .name>span{
  vertical-align: middle;
}
.tree-view-item .name>span.unfold:hover,
.tree-view-item .name>span.fold:hover{
  color:#39f;
}
.tree-view-item .level{
  width:100%;
  line-height: 24px;
}
.tree-view-item .level>div{
  font-size:0;
}
.tree-view-item .heading-children{
  padding-left:0;
}
.tree-view-item .level>div .statusShow,
.tree-view-item .level>div .gradeShow,
.tree-view-item .level>div .operate,
.tree-view-item .level>div .name{
  display: inline-block;
  font-size:14px;
  text-align: center;
  border-width:0 1px 1px 0;
  border-color:#ccc;
  border-style:solid;
  height:32px;
  line-height: 32px;
  box-sizing:border-box;
}
.tree-view-item .level>div .itemCode{
  font-size: 14px;
  display: inline-block;
  text-align: center;
  color: #000;
  width:17.13%;
  box-sizing: border-box;
  height: 32px;
  line-height: 32px;
  border-left: 1px solid #ccc;
  border-bottom: 1px solid #ccc;
}

.tree-view-item .level>div .name{
  width:31.47%;
  border-left:1px solid #ccc;
  text-align: left;
}
.tree-view-item .level>div .statusShow,
.tree-view-item .level>div .gradeShow,
.tree-view-item .level>div .operate{
  width:17.13%;
}
.tree-view-item .level-1 .name{
  padding-left:14.5%;
}
.tree-view-item .level-2 .name{
  padding-left:15.5%;
}
.tree-view-item .level-3 .name{
  padding-left:16.5%;
}
.tree-view-item .level-4 .name{
  padding-left:17.5%;
}
.tree-view-item .operate >span{
  cursor: pointer;
}
.tree-view-item .operate >span:hover{
  color:#39f;
}
</style>