From e1c87bdacc24cf65d0c1b2e9f484e9a7f19256dd Mon Sep 17 00:00:00 2001
From: DerThorsten <derthorstenbeier@gmail.com>
Date: Thu, 20 Nov 2025 10:35:57 +0100
Subject: [PATCH 1/2] 4x updates

---
 include/xeus-javascript/convert_json.hpp | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/xeus-javascript/convert_json.hpp b/include/xeus-javascript/convert_json.hpp
index 8f495ff..043f94d 100644
--- a/include/xeus-javascript/convert_json.hpp
+++ b/include/xeus-javascript/convert_json.hpp
@@ -48,18 +48,18 @@ struct BindingType<nl::json> {
 };
 
 
-template <typename T>
-using is_decayed_json = std::is_same<std::decay_t<T>, nl::json>;
+// template <typename T>
+// using is_decayed_json = std::is_same<std::decay_t<T>, nl::json>;
 
-template <typename T>
-using enable_if_decayed_json = typename std::enable_if<is_decayed_json<T>::value, void>::type;
+// template <typename T>
+// using enable_if_decayed_json = typename std::enable_if<is_decayed_json<T>::value, void>::type;
 
-template<class T>
-struct TypeID<T, enable_if_decayed_json<T> > {
-    static constexpr TYPEID get() {
-        return LightTypeID<val>::get();
-    }
-};
+// template<class T>
+// struct TypeID<nlohmann::json>
+//     static constexpr TYPEID get() {
+//         return LightTypeID<val>::get();
+//     }
+// };
 
 
 

From 649ddbe0c30aadee6a16630b1491bdf19d532a83 Mon Sep 17 00:00:00 2001
From: DerThorsten <derthorstenbeier@gmail.com>
Date: Tue, 25 Nov 2025 09:24:20 +0100
Subject: [PATCH 2/2] unify

---
 CMakeLists.txt                           |  6 +++
 include/xeus-javascript/convert_json.hpp | 61 +++++-------------------
 2 files changed, 18 insertions(+), 49 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a5d435d..653f42d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -60,6 +60,12 @@ if(EMSCRIPTEN)
     SET(XEUS_JAVASCRIPT_USE_SHARED_XEUS ON)
     SET(XEUS_JAVASCRIPT_USE_SHARED_XEUS_JAVASCRIPT OFF)
     SET(XEUS_JAVASCRIPT_BUILD_TESTS OFF)
+
+
+    if (EMSCRIPTEN_VERSION VERSION_LESS "4.0.0")
+        # c-definitions for older emscripten versions
+        add_compile_definitions(XEUS_JAVASCRIPT_EMSCRIPTEN_OLD)
+    endif()
 endif()
 
 
diff --git a/include/xeus-javascript/convert_json.hpp b/include/xeus-javascript/convert_json.hpp
index 043f94d..6e37385 100644
--- a/include/xeus-javascript/convert_json.hpp
+++ b/include/xeus-javascript/convert_json.hpp
@@ -47,60 +47,23 @@ struct BindingType<nl::json> {
     }
 };
 
+#ifdef XEUS_JAVASCRIPT_EMSCRIPTEN_OLD
 
-// template <typename T>
-// using is_decayed_json = std::is_same<std::decay_t<T>, nl::json>;
 
-// template <typename T>
-// using enable_if_decayed_json = typename std::enable_if<is_decayed_json<T>::value, void>::type;
+template <typename T>
+using is_decayed_json = std::is_same<std::decay_t<T>, nl::json>;
 
-// template<class T>
-// struct TypeID<nlohmann::json>
-//     static constexpr TYPEID get() {
-//         return LightTypeID<val>::get();
-//     }
-// };
+template <typename T>
+using enable_if_decayed_json = typename std::enable_if<is_decayed_json<T>::value, void>::type;
 
+template<class T>
+struct TypeID<T, enable_if_decayed_json<T> > {
+    static constexpr TYPEID get() {
+        return LightTypeID<val>::get();
+    }
+};
 
-
-
-
-
-// template <>
-// struct TypeID<nl::json> {
-//     static constexpr TYPEID get() {
-//         return LightTypeID<val>::get();
-//     }
-// };
-
-// template <>
-// struct TypeID<const nl::json> {
-//     static constexpr TYPEID get() {
-//         return LightTypeID<val>::get();
-//     }
-// };
-
-// template <>
-// struct TypeID< nl::json  && > {
-//     static constexpr TYPEID get() {
-//         return LightTypeID<val>::get();
-//     }
-// };
-
-
-// template <>
-// struct TypeID<nl::json&> {
-//     static constexpr TYPEID get() {
-//         return LightTypeID<val>::get();
-//     }
-// };
-
-// template <>
-// struct TypeID<const nl::json&> {
-//     static constexpr TYPEID get() {
-//         return LightTypeID<val>::get();
-//     }
-// };
+#endif
 
 }  // namespace internal
 }  // namespace emscripten