diff --git a/src/Api/Resolver/FacetsResolver.php b/src/Api/Resolver/FacetsResolver.php
index da9bc7d3..abb87c69 100644
--- a/src/Api/Resolver/FacetsResolver.php
+++ b/src/Api/Resolver/FacetsResolver.php
@@ -48,7 +48,7 @@ public function resolve(array $data): array
         }
 
         return array_filter($adapter->getAggregations(), function ($facet) {
-            return [] !== $facet['buckets'] ?? [];
+            return [] !== ($facet['buckets'] ?? []);
         });
     }
 }