elementui中树形控件默认选中（不设置show-checkbox）

<el-tree
	ref="tree"
	node-key="id"
	:data="deviceTree"
	:check-strictly="true"
	:props="defaultProps"
	:highlight-current="true"
	:expand-on-click-node="false"
   :default-expand-all="true"
	@node-click="handleNodeClick"
></el-tree>

this.$(id) // id为deviceTree里面对应的id值