Items can be saved to JSON file "items.json" (in standard location).

model/modelitem.h

@@ -12,6 +12,9 @@ class ModelItem {
   // TODO change return value to list of changed roles
   bool setItemData(const QMap<int, QVariant>& changedValues);
 
+  // QString toString() const;
+  QJsonObject toJsonObject() const;
+
  private:
   QHash<int, QVariant> m_values;
 };