diff --git a/src/Encoder/Transformers/ModelTransformer.php b/src/Encoder/Transformers/ModelTransformer.php
index 7490520..03ad503 100644
--- a/src/Encoder/Transformers/ModelTransformer.php
+++ b/src/Encoder/Transformers/ModelTransformer.php
@@ -42,15 +42,15 @@ public function transform($model)
             Key::META          => $this->serializeMetaData($resource),
         ];
 
-        if ( ! count($data[ Key::ATTRIBUTES ])) {
+        if ( ! count((array) $data[ Key::ATTRIBUTES ])) {
             unset($data[ Key::ATTRIBUTES ]);
         }
 
-        if ( ! count($data[ Key::RELATIONSHIPS ])) {
+        if ( ! count((array) $data[ Key::RELATIONSHIPS ])) {
             unset($data[ Key::RELATIONSHIPS ]);
         }
 
-        if ( ! count($data[ Key::META ])) {
+        if ( ! count((array) $data[ Key::META ])) {
             unset($data[ Key::META ]);
         }