use 'readTree' to parse data file

src/misc/b3util.ts

@@ -652,8 +652,7 @@ export const createTreeData = (
 
 export const createBuildData = (path: string) => {
   try {
-    const str = fs.readFileSync(path, "utf8");
-    const treeModel: TreeModel = JSON.parse(str);
+    const treeModel: TreeModel = readTree(path);
     const data = createTreeData(treeModel.root);
     refreshTreeDataId(data, treeModel.firstid ?? 1);
     treeModel.name = Path.basenameWithoutExt(path);

src/misc/util.ts

@@ -8,7 +8,12 @@ export const readJson = (path: string) => {
 
 export const readTree = (path: string) => {
   const str = fs.readFileSync(path, "utf-8");
-  return JSON.parse(str) as TreeModel;
+  const data = JSON.parse(str) as TreeModel;
+  data.firstid = data.firstid ?? 1;
+  data.group = data.group || [];
+  data.import = data.import || [];
+  data.declvar = data.declvar || [];
+  return data;
 };
 
 export const writeJson = (path: string, data: any) => {