feat: 深度为4的节点不再显示创建子节点按钮

src/components/Tree.vue

@@ -8,6 +8,7 @@
         :key="item.id"
         :position-x="index"
         :node-style="NODE_STYLE"
+        :depth="item.deep"
         @addChild="addChild"
         @deleteNode="deleteNode"
         @nodeClick="nodeClick"

src/components/TreeNode.vue

@@ -12,7 +12,9 @@
     </div>
     <div class="node-postfix">
       <div class="icon" target="delete" @click="deleteNode(id)"></div>
-      <div class="icon" target="add" @click="addChild(id)"></div>
+      <template v-if="depth!==4">
+        <div class="icon" target="add" @click="addChild(id)"></div>
+      </template>
     </div>
   </div>
 </template>
@@ -38,6 +40,7 @@ export default {
     positionY: Number,
     positionX: Number,
     nodeStyle: Object,
+    depth: Number,
   },
   computed: {
     containerStyle() {