vue3+ts+elementui-plus二次封装树形表格实现不同层级展开收起的功能

一、TableTreeLevel组件 

<template>
      <div class='main'>
            <div class="btns">
                  <el-button type="primary" @click="expandLevel(1)">展开一级</el-button>
                  <el-button type="primary" @click="expandLevel(2)">展开二级</el-button>
                  <el-button type="primary" @click="expandLevel(3)">展开三级</el-button>
                  <el-button type="primary" @click="expandLevel(4)">展开四级</el-button>
                  <el-button type="warning" @click="putAwayLevel(0)">全部收起</el-button>
            </div>
            <div>
                  <el-table ref="multipleTableRef" :height="height" :default-expand-all=