elment 中tree组件展开所有和收缩所有节点

 //收起所有节点
            setCheckedKeys() {
                this.defaultExpand = false;
                for (var i = 0; i < this.$refs.tree.store._getAllNodes().length; i++) {
                     if (this.$refs.tree.store._getAllNodes()[i].id !== 1) {
                         this.$refs.tree.store._getAllNodes()[i].expanded = this.defaultExpand;
                    }
                }
            },

            setCheckedNodes() {
                this.defaultExpand = true; //展开所有节点
                for (var i = 0; i < this.$refs.tree.store._getAllNodes().length; i++) {
                    this.$refs.tree.store._getAllNodes()[i].expanded = this.defaultExpand;
                   
                }
            }

<el-tree :data="deptData" :props="defaultProps" v-loading="listLoading" :default-expanded-keys="idArr" @@node-click="handleNodeClick" node-key="Id"
                         :expand-on-click-node="true"
                         :filter-node-method="filterNode"
                         :render-content="renderContent" ref="tree">
                </el-tree>

 <div>
            <iclass="arrow-down el-icon-arrow-down" @click="allExpand(true)" title="展开所有"></i>
            <iclass="arrow-down el-icon-arrow-up" @click="allExpand(false)" titie="收缩所有"></i>

 </div>

 <el-tree
                    :data="AiditReportData"
                    node-key="id"
                    ref="selectTree"
                    :default-expand-all="true"
                    :default-expanded-keys="defaultExpandArr"
                >



 upAll () {
    // 全部展开  遍历变成true
    let self = this;
    // 将没有转换成树的原数据
    let treeList = this.sourceData;
    for (let i = 0; i < treeList.length; i++) {
    // 将没有转换成树的原数据设置key为... 的展开
    self.$refs.selectTree.store.nodesMap[treeList[i].id].expanded = true
    }
},


  public allExpand(isExpand: boolean) {
      const that: any = this;
      const treeList = this.AiditReportData;
      console.log('isExpand', isExpand);
      for (let i = 0; i < treeList.length; i++) {
        that.$refs.selectTree.store.nodesMap[treeList[i].id].expanded = isExpand;
      }

  }


//原文：https://www.cnblogs.com/ll15888/p/12002745.html