JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//unpkg.com/vue/dist/vue.js"></script>
<script src="//unpkg.com/element-ui/lib/index.js"></script>
<div id="app">
  <span>选择需要选中的节点 ID</span>
  <el-select v-model="checkedKey" @change="setCheckedKey">
    <el-option v-for="i in 10" :value="i" :label="i"></el-option>
  </el-select>
  <el-tree :data="data2" show-checkbox node-key="id" ref="tree" highlight-current :default-expanded-keys="expandedKeys">
  </el-tree>
</div>

SCSS

@import url("//unpkg.com/element-ui/lib/theme-chalk/index.css");

Babel + JSX

var Main = {
    methods: {
      setCheckedKey(id) {
        this.$refs.tree.setCheckedKeys([id]);
        console.log('看');
        console.log(this.$refs.tree)
        let targetNode = this.$refs.tree.store.nodesMap[id];
        const path = [];
        while (targetNode.parent && targetNode.parent.data.id) {
          path.push(targetNode.parent.data.id);
          targetNode = targetNode.parent;
        }
        this.expandedKeys = path;
      }
    },

    data() {
      return {
        expandedKeys: [],
        checkedKey: '',
        data2: [{
          id: 1,
          label: '一级 1',
          children: [{
            id: 4,
            label: '二级 1-1',
            children: [{
              id: 9,
              label: '三级 1-1-1'
            }, {
              id: 10,
              label: '三级 1-1-2'
            }]
          }]
        }, {
          id: 2,
          label: '一级 2',
          children: [{
            id: 5,
            label: '二级 2-1'
          }, {
            id: 6,
            label: '二级 2-2'
          }]
        }, {
          id: 3,
          label: '一级 3',
          children: [{
            id: 7,
            label: '二级 3-1'
          }, {
            id: 8,
            label: '二级 3-2'
          }]
        }]
      };
    }
  };
var Ctor = Vue.extend(Main)
new Ctor().$mount('#app')