Demo：update

web/src/api/index.js

@@ -14,6 +14,7 @@ let mindMapData = null
  * @Desc: 克隆思维导图数据，去除激活状态
  */
 const copyMindMapTreeData = (tree, root) => {
+  if (!root) return null
   tree.data = simpleDeepClone(root.data)
   // tree.data.isActive = false
   tree.children = []

web/src/pages/Edit/components/Count.vue

@@ -70,6 +70,7 @@ export default {
      * @Desc: 遍历
      */
     walk(data) {
+      if (!data) return
       this.num++
       this.textStr += String(data.data.text) || ''
       if (data.children && data.children.length > 0) {

web/src/pages/Edit/components/ToolbarNodeBtnList.vue

@@ -179,7 +179,7 @@ export default {
   data() {
     return {
       activeNodes: [],
-      backEnd: false,
+      backEnd: true,
       forwardEnd: true,
       readonly: false,
       isFullDataFile: false,