diff --git a/lib/Core/FieldType/RichText/Indexable.php b/lib/Core/FieldType/RichText/Indexable.php
index 0180362c..17aafcca 100644
--- a/lib/Core/FieldType/RichText/Indexable.php
+++ b/lib/Core/FieldType/RichText/Indexable.php
@@ -29,7 +29,7 @@ public function __construct($shortTextMaxLength = 256)
         $this->shortTextMaxLength = $shortTextMaxLength;
     }
 
-    public function getIndexData(Field $field, FieldDefinition $fieldDefinition)
+    public function getIndexData(Field $field, FieldDefinition $fieldDefinition): array
     {
         $document = new DOMDocument();
         $document->loadXML($field->value->data);