diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceReferencedEntityFieldFormatter.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceReferencedEntityFieldFormatter.php
index 8a492cf..b7eb458 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceReferencedEntityFieldFormatter.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceReferencedEntityFieldFormatter.php
@@ -171,7 +171,7 @@ protected function getAvailableFieldNames() {
       $field_names = [];
     }
 
-    $target_bundles = $this->fieldDefinition->getSetting('handler_settings')['target_bundles'] === NULL ? array_keys($this->entityTypeBundleInfo->getBundleInfo($entity_type_id)) : $this->fieldDefinition->getSetting('handler_settings')['target_bundles'];
+    $target_bundles = empty($this->fieldDefinition->getSetting('handler_settings')['target_bundles']) ? array_keys($this->entityTypeBundleInfo->getBundleInfo($entity_type_id)) : $this->fieldDefinition->getSetting('handler_settings')['target_bundles'];
     foreach ($target_bundles as $value) {
       $bundle_field_names = array_map(
         function (FieldDefinitionInterface $field_definition) {