From 1ed1d1ef4b26dbeacb2386f754b30d8e4dcb30af Mon Sep 17 00:00:00 2001
From: Tom Duncalf <tom.duncalf@mongodb.com>
Date: Fri, 9 Sep 2022 12:42:07 +0100
Subject: [PATCH] Change to empty string for internal field name

---
 src/jsi/jsi_class.hpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/jsi/jsi_class.hpp b/src/jsi/jsi_class.hpp
index aaace099fa..253234a717 100644
--- a/src/jsi/jsi_class.hpp
+++ b/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>;