update Tree

examples/routers/tree.vue

@@ -5,6 +5,7 @@
     export default {
         data () {
             return {
+                bd: [],
                 baseData: [
                     {
                         expand: true,

src/components/tree/tree.vue

@@ -8,6 +8,7 @@
             :multiple="multiple"
             :show-checkbox="showCheckbox">
         </Tree-node>
+        <div :class="[prefixCls + '-empty']" v-if="!data.length">{{ emptyText }}</div>
     </div>
 </template>
 <script>