diff --git a/Userland/Libraries/LibJS/Runtime/Shape.h b/Userland/Libraries/LibJS/Runtime/Shape.h
index 89dad6cfeb..6d78b3570e 100644
--- a/Userland/Libraries/LibJS/Runtime/Shape.h
+++ b/Userland/Libraries/LibJS/Runtime/Shape.h
@@ -43,7 +43,7 @@ class Shape final
 public:
     virtual ~Shape() override = default;
 
-    enum class TransitionType {
+    enum class TransitionType : u8 {
         Invalid,
         Put,
         Configure,