diff --git a/filter.js b/filter.js
index 29851f4..402b67d 100644
--- a/filter.js
+++ b/filter.js
@@ -1,3 +1,10 @@
+/*
+ * Copyright (C) Sapphirecode - All Rights Reserved
+ * This file is part of utilities which is released under MIT.
+ * See file 'LICENSE' for full license details.
+ * Created by Timo Hocker <timo@scode.ovh>, November 2020
+ */
+
 'use strict';
 
 function get_element_field (element, carried_data, field) {
diff --git a/stryker.conf.js b/stryker.conf.js
index aded96a..6a73a97 100644
--- a/stryker.conf.js
+++ b/stryker.conf.js
@@ -19,5 +19,11 @@ module.exports = {
   testRunner:        'jasmine',
   jasmineConfigFile: 'jasmine.json',
   coverageAnalysis:  'perTest',
-  mutate:            [ 'index.js' ]
+  mutate:            [
+    '**/*.js',
+    '**/*.ts',
+    '!**/test/**/*',
+    '!**/spec/**/*',
+    '!stryker.conf.js'
+  ]
 };