diff --git a/lib/src/common/js_proxy.dart b/lib/src/common/js_proxy.dart
index 09fa84b..1bb5f44 100644
--- a/lib/src/common/js_proxy.dart
+++ b/lib/src/common/js_proxy.dart
@@ -59,6 +59,7 @@ class JsProxyReflectable extends Reflectable {
             typeCapability,
             typeRelationsCapability,
             subtypeQuantifyCapability,
+            superclassQuantifyCapability,
             const StaticInvokeCapability('hostAttributes'));
 }