element中树形数据与懒加载实现全部展开和全部收起

<template>
    <div class="app-container">
      <el-form :inline="true" label-width="90px">
        <el-form-item>
          <el-button v-if="open" type="primary" style="margin-bottom:10px;" @click="Toexpandall">全部展开</el-button>
          <el-button v-if="close" type="primary" style="margin-bottom:10px;" @click="ToClose">全部收起</el-button>
        </el-form-item>
      </el-form>
      <el-table
        v-loading="loading"
        row-key="svrId"
        ref="tabletree"
        :data="treeList" 
        :default-expand-all="false"
        :tree-props="{children: ‘children‘, hasChildren: ‘hasChildren‘}">
        <el-table-column prop="svrName" label="姓名"></el-table-column>
        <el-table-column prop="svrTypeName" label="服务商类型" align="center" ></el-table-column>
        <el-table-column prop="svrMobile" label="手机号" align="center" ></el-table-column>
        <el-table-column prop="svrId" label="账号" align="center" ></el-table-column>
        <el-table-column prop="businessLevelName" label="等级" align="center" ></el-table-column>
      </el-table>
    </div>
</template>

<script>
import { treelist } from "@/api/svrmanage/apply"
export default {
  name: "treeList",
  data() {
    return {
      // 遮罩层
      loading: true,
      // 表格树数据
      treeList: [],
      open: true,
      close:false,
    };
  },
  created() {
    this.getList();
  },
  methods: {
    /** 查询部门列表 在这里调后端接口进行数据渲染 */
    getList() {
      this.loading = true;
      treelist().then(response => {
        if(response.code === 200) {
          this.treeList = response.data;
          this.loading = false;
        }
      });
    },
    // 全部展开
    Toexpandall() {
      let els = document.getElementsByClassName(‘el-table__expand-icon‘)
      if(this.treeList.length !=0 && els.length != 0){
        this.open = false
        this.close = true
        for(let j1=0;j1<els.length;j1++){
          els[j1].classList.add("dafult") 
        }
        if(this.$el.getElementsByClassName(‘el-table__expand-icon--expanded‘)){
          const open = this.$el.getElementsByClassName(‘el-table__expand-icon--expanded‘)
          for(let j=0;j<open.length;j++){
            open[j].classList.remove("dafult")
            // open[j].classList.remove("el-table__expand-icon--expanded")
            // open[j].click(function(event) {
            //   event.preventDefault();
            // })
          }
          const dafult = this.$el.getElementsByClassName(‘dafult‘)
          for(let a=0;a<dafult.length;a++){
            dafult[a].click()
          }
        }
      }
    },
    // 全部收起
    ToClose() {
      if(this.treeList.length !=0){
        this.open = true
        this.close = false
        const elsopen = this.$el.getElementsByClassName(‘el-table__expand-icon--expanded‘)
        if(this.$el.getElementsByClassName(‘el-table__expand-icon--expanded‘)){
          for(let i=0;i<elsopen.length;i++){
            elsopen[i].click()
          }
        }
      }
    }
  }
};
</script>