elementui的tree树形控件获取所有选中的节点

<el-tree :props="defaultParams"
                   ref="tree"
                   :data="treedata"
                   show-checkbox
                   node-key="id"
                   @check-change="handleCheckChange">
          </el-tree>

defaultParams: {
        label: 'name',
        children: 'childList'
      }

getCheckedNodes：返回目前被选中的节点所组成的数组

handleCheckChange () {
      let res = this.$refs.tree.getCheckedNodes()
      let arr = []
      res.forEach((item) => {
        arr.push(item.id)
      })
      let menuArr = this.unique(arr); // 去除重复的节点
      this.permissionIds = menuArr.join(',')
    },
// 数组去重
    unique (arr) {
      let newArr = []
      let len = arr.length
      for (let i = 0; i < len; i++) {
        if (newArr.indexOf(arr[i]) == -1) {
          newArr.push(arr[i])
        }
      }
      return newArr
    }

 

// 取消所有选中

handleCancelSelect(){
    this.$refs.tree.setCheckedKeys([]);
}