diff --git a/Models/NullNavElement.php b/Models/NullNavElement.php
index 24b5eb5..7c662ea 100755
--- a/Models/NullNavElement.php
+++ b/Models/NullNavElement.php
@@ -35,4 +35,12 @@ final class NullNavElement extends NavElement
     {
         $this->id = $id;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function jsonSerialize() : mixed
+    {
+        return ['id' => $this->id];
+    }
 }