Issue #3339527: Coding standards

modules/jsonapi_defaults/src/Controller/EntityResource.php

@@ -171,7 +171,7 @@ class EntityResource extends JsonApiEntityResourse {
       );
       throw new \LengthException($message);
     }
-    return isset($relatable_resource_types[0]) ? $relatable_resource_types[0] : NULL;
+    return $relatable_resource_types[0] ?? NULL;
   }
 
   /**