1 files changed, 1 insertions, 1 deletions
diff --git a/src/lua.js b/src/lua.js
index 58cc0cd..6ebf250 100644
--- a/src/lua.js
+++ b/src/lua.js
@@ -68,7 +68,7 @@ const LUA_MINSTACK = 20;
 const LUA_REGISTRYINDEX = -luaconf.LUAI_MAXSTACK - 1000;
 
 const lua_upvalueindex = function(i) {
-    LUA_REGISTRYINDEX - i;
+    return LUA_REGISTRYINDEX - i;
 };
 
 /* predefined values in the registry */