diff --git a/www/src/models/transformation/TransformationResult.ts b/www/src/models/transformation/TransformationResult.ts
index 3eba47b..4554fff 100644
--- a/www/src/models/transformation/TransformationResult.ts
+++ b/www/src/models/transformation/TransformationResult.ts
@@ -1,6 +1,6 @@
 export interface TransformationResult {
   path: number;
   value: string;
-  ok: string | boolean;
-  error: string;
+  ok: any[] | any | undefined;
+  error: string | undefined;
 }
diff --git a/www/src/pages/table/forms/TransformationForm.tsx b/www/src/pages/table/forms/TransformationForm.tsx
index 8d4fc85..8b8d3d7 100644
--- a/www/src/pages/table/forms/TransformationForm.tsx
+++ b/www/src/pages/table/forms/TransformationForm.tsx
@@ -273,6 +273,6 @@ function transformationResult2Row(tbl: TransformationResult) {
     key: tbl.path,
     row_id: tbl.path + 1,
     previous_value: tbl.value,
-    result: tbl.ok !== undefined ? tbl.ok : tbl.error.trim(),
+    result: tbl.ok !== undefined ? tbl.ok : tbl.error!.trim(),
   };
 }