Change to empty string for internal field name

src/jsi/jsi_class.hpp

@@ -145,7 +145,10 @@ inline void copyProperty(JsiEnv env, const fbjsi::Object& from, const fbjsi::Obj
     defineProperty(env, to, name, *prop);
 }
 
-inline constexpr const char g_internal_field[] = "__Realm_internal";
+// The name used for the property on the JS object which stores the reference to the corresponding C++ object.
+// We use an empty string as testing showed it was 1% faster with JSC and 4% faster with Hermes than using
+// an actual string, and also has the benefit that it is not a valid Realm object key name.
+inline constexpr const char g_internal_field[] = "";
 
 template <typename T>
 using ClassDefinition = js::ClassDefinition<js::realmjsi::Types, T>;
@@ -672,7 +675,8 @@ class ObjectWrap {
 } // namespace realmjsi
 
 template <typename ClassType>
-class ObjectWrap<realmjsi::Types, ClassType> : public realm::js::realmjsi::ObjectWrap<ClassType> {};
+class ObjectWrap<realmjsi::Types, ClassType> : public realm::js::realmjsi::ObjectWrap<ClassType> {
+};
 
 template <realmjsi::ArgumentsMethodType F>
 fbjsi::Value wrap(fbjsi::Runtime& rt, const fbjsi::Value& thisVal, const fbjsi::Value* args, size_t count)