1、需求：点击树形控件中的某个节点，需要拿到它本身和底下所有的子节点的id

1、树形控件代码

  <el-tree
                            :data="deptOptions"
                            @node-click="getVisitCheckedNodes"
                            ref="target_tree_Speech"
                            node-key="id"
                            :default-expanded-keys="[
                              '00',
                              'SPACE_FIRST_SUBJECT'
                            ]"
                            :highlight-current="true"
                            :filter-node-method="filterNodeIndex"
                            :check-strictly="!form.deptCheckStrictly"
                            empty-text="暂无数据"
                            :props="defaultPropsIndex"
                          >
                          </el-tree>

2、点击事件代码

   // 点击访问权限树形控件的事件visitRightUser
    getVisitCheckedNodes(node, e) {
      console.log('!!!', node);
   
        this.visit_id_result = node.id;
        this.visit_result = node.id;
        this.breadList = [];
        this.childList = [];
        this.nodeList = [];
        this.flag = 0;
        console.log('当前点击的节点数据', e);
        this.getTreeNode(e);
        //-------------------获取子节点数据函数
        this.getTreeNodeChild(e);
        // 把当前点击的节点的id先放入数组中
        this.breadList.unshift(e.data.id);
        this.breadList = this.unique(this.breadList);
        // console.log('节点数据', e);
        console.log('所有的子节点数据', this.unique(this.childList));
        this.visit_level = node.level;
        this.visit_name = node.name;
        this.get_have_visit_data_user(node.id);
        this.$nextTick(() => {
          this.$refs.treeSpeech.setCurrentKey(this.visit_id_result);
        });
    
    },

3、获取子节点函数

 // 递归获取当前选中节点的所有子节点
    getTreeNodeChild(node) {
      console.log('当前遍历节点的数据', node);
      if (node.data.id) {
        this.childList.unshift(node.data.id);
      }
      //获取当前树节点和其子级节点
      if (node.childNodes.length) {
        for (let index = 0; index < node.childNodes.length; index++) {
          this.nodeList.push(node.childNodes[index]);
          if (node.childNodes[index].data.id) {
            this.childList.unshift(node.childNodes[index].data.id); //在数组头部添加元素
          }
        }
      }
      console.log('本身节点加上子节点', this.childList);
      console.log('下次需要遍历的节点', this.nodeList);
     if (this.flag) {
        this.nodeList.shift();
        console.log('777', this.nodeList[0]);
        if (this.nodeList[0] !== undefined) {
          this.getTreeNodeChild(this.nodeList[0]);
        }
      }
      // flag标识判断是否是第一次执行这个函数，如果是第一次执行就走这里，后面执行的需要先删除第一个在进行函数
      this.flag = 1;
      if (this.nodeList[0] !== undefined) {
        this.getTreeNodeChild(this.nodeList[0]);
      }
    },

效果图：