diff --git a/.github/workflows/ubuntu_20.yml b/.github/workflows/ubuntu_20.yml
index 20404849..5259c8b6 100644
--- a/.github/workflows/ubuntu_20.yml
+++ b/.github/workflows/ubuntu_20.yml
@@ -16,7 +16,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - uses: awalsh128/cache-apt-pkgs-action@v1.3.0
+      - uses: awalsh128/cache-apt-pkgs-action@latest
         with:
           packages: libwebkit2gtk-4.0-dev libcurl4-openssl-dev libcrypto++-dev ninja-build
 
diff --git a/.github/workflows/ubuntu_22.yml b/.github/workflows/ubuntu_22.yml
index 7c7077d9..21e62901 100644
--- a/.github/workflows/ubuntu_22.yml
+++ b/.github/workflows/ubuntu_22.yml
@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - uses: awalsh128/cache-apt-pkgs-action@v1.3.0
+      - uses: awalsh128/cache-apt-pkgs-action@latest
         with:
           packages: libwebkit2gtk-4.0-dev libcurl4-openssl-dev libcrypto++-dev ninja-build
 
diff --git a/cmake/backend/emscripten.cmake b/cmake/backend/emscripten.cmake
index cf6986bb..c13496a2 100644
--- a/cmake/backend/emscripten.cmake
+++ b/cmake/backend/emscripten.cmake
@@ -130,6 +130,9 @@ function(nui_add_emscripten_target)
         set(PATCH_DOTENV_COMMAND COMMAND cmake -E true)
     endif()
 
+    get_target_property(TARGET_CXX_STANDARD ${NUI_ADD_EMSCRIPTEN_TARGET_ARGS_TARGET} CXX_STANDARD)
+    message(STATUS "C++ standard of frontend subproject: ${TARGET_CXX_STANDARD}")
+
     include(ExternalProject)
     ExternalProject_Add(
         "${NUI_ADD_EMSCRIPTEN_TARGET_ARGS_TARGET}-emscripten"
@@ -137,6 +140,7 @@ function(nui_add_emscripten_target)
         # emscripten cmake with passed down Release/Debug build type
         CONFIGURE_COMMAND
             ${EMCMAKE} cmake
+                "-DCMAKE_CXX_STANDARD=${TARGET_CXX_STANDARD}"
                 ${NUI_ADD_EMSCRIPTEN_TARGET_ARGS_CMAKE_OPTIONS}
                 "-DNUI_NPM=${NUI_NPM}"
                 "-DNUI_NODE=${NUI_NODE}"
diff --git a/cmake/frontend/emscripten.cmake b/cmake/frontend/emscripten.cmake
index c1cd356d..f6b13933 100644
--- a/cmake/frontend/emscripten.cmake
+++ b/cmake/frontend/emscripten.cmake
@@ -2,7 +2,7 @@ function(nui_prepare_emscripten_target)
     cmake_parse_arguments(
         NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS
         "NO_INLINE;NO_INLINE_INJECT;LEAN_INDEX_HTML"
-        "TARGET;PREJS;STATIC;UNPACKED_MODE"
+        "TARGET;PREJS;STATIC;UNPACKED_MODE;CXX_STANDARD"
         "EMSCRIPTEN_LINK_OPTIONS;EMSCRIPTEN_COMPILE_OPTIONS;PARCEL_ARGS;NPM_INSTALL_ARGS;OBSERVED_BUNDLE_FILES"
         ${ARGN}
     )
@@ -28,9 +28,13 @@ function(nui_prepare_emscripten_target)
         set(NUI_LEAN_HTML "lean")
     endif()
 
+    if (NOT NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_CXX_STANDARD)
+        get_target_property(NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_CXX_STANDARD ${NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_TARGET} CXX_STANDARD)
+    endif()
+
     set(INLINER_COMMAND "")
     if (NOT NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_NO_INLINE)
-        nui_enable_inline(TARGET ${NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_TARGET} RELATIVE_TO ${CMAKE_CURRENT_SOURCE_DIR})
+        nui_enable_inline(TARGET ${NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_TARGET} RELATIVE_TO ${CMAKE_CURRENT_SOURCE_DIR} CXX_STANDARD ${NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_CXX_STANDARD})
         if (NOT NUI_PREPARE_EMSCRIPTEN_TARGET_ARGS_NO_INLINE_INJECT)
             set(INLINER_COMMAND COMMAND ${NUI_INLINE_INJECTOR_TARGET_FILE} "${CMAKE_BINARY_DIR}/static/index.html" "${CMAKE_BINARY_DIR}/nui-inline/inline_imports.js" "${CMAKE_BINARY_DIR}/nui-inline/inline_imports.css" ${NUI_DEFER_INLINE_SCRIPTS_TAG} ${NUI_LEAN_HTML})
         endif()
diff --git a/nui/include/nui/event_system/listen.hpp b/nui/include/nui/event_system/listen.hpp
index c87c2818..26b961c0 100644
--- a/nui/include/nui/event_system/listen.hpp
+++ b/nui/include/nui/event_system/listen.hpp
@@ -6,9 +6,20 @@
 #include <utility>
 #include <memory>
 #include <functional>
+#include <type_traits>
 
 namespace Nui
 {
+    namespace Detail
+    {
+        template <typename>
+        struct IsStdFunction : std::false_type
+        {};
+        template <typename RetT, typename... ArgsT>
+        struct IsStdFunction<std::function<RetT(ArgsT...)>> : std::true_type
+        {};
+    }
+
     template <typename ValueT>
     void listen(EventContext& eventContext, Observed<ValueT> const& obs, std::function<bool(ValueT const&)> onEvent)
     {
@@ -22,6 +33,20 @@ namespace Nui
         obs.attachEvent(eventId);
     }
 
+    template <typename ValueT>
+    requires std::is_scalar_v<ValueT>
+    void listen(EventContext& eventContext, Observed<ValueT> const& obs, std::function<bool(ValueT)> onEvent)
+    {
+        const auto eventId = eventContext.registerEvent(Event{
+            [obs = Detail::CopyableObservedWrap{obs}, onEvent = std::move(onEvent)](auto) {
+                return onEvent(obs.value());
+            },
+            []() {
+                return true;
+            }});
+        obs.attachEvent(eventId);
+    }
+
     template <typename ValueT>
     void listen(EventContext& eventContext, Observed<ValueT> const& obs, std::function<void(ValueT const&)> onEvent)
     {
@@ -31,10 +56,23 @@ namespace Nui
         });
     }
 
+    template <typename ValueT>
+    requires std::is_scalar_v<ValueT>
+    void listen(EventContext& eventContext, Observed<ValueT> const& obs, std::function<void(ValueT)> onEvent)
+    {
+        return listen(eventContext, obs, [onEvent = std::move(onEvent)](ValueT value) {
+            onEvent(value);
+            return true;
+        });
+    }
+
     template <typename ValueT, typename FunctionT>
-    void listen(EventContext& eventContext, Observed<ValueT> const& obs, FunctionT onEvent)
+    requires(
+        (std::invocable<FunctionT, ValueT const&> || std::invocable<FunctionT, ValueT>) &&
+        !Detail::IsStdFunction<FunctionT>::value)
+    void listen(EventContext& eventContext, Observed<ValueT> const& obs, FunctionT&& onEvent)
     {
-        return listen(eventContext, obs, std::function(std::move(onEvent)));
+        return listen(eventContext, obs, std::function(std::forward<FunctionT>(onEvent)));
     }
 
     template <typename ValueT>
@@ -55,6 +93,25 @@ namespace Nui
         obs->attachEvent(eventId);
     }
 
+    template <typename ValueT>
+    requires std::is_scalar_v<ValueT>
+    void listen(
+        EventContext& eventContext,
+        std::shared_ptr<Observed<ValueT>> const& obs,
+        std::function<bool(ValueT)> onEvent)
+    {
+        const auto eventId = eventContext.registerEvent(Event{
+            [weak = std::weak_ptr<Observed<ValueT>>{obs}, onEvent = std::move(onEvent)](auto) {
+                if (auto obs = weak.lock(); obs)
+                    return onEvent(obs->value());
+                return false;
+            },
+            [weak = std::weak_ptr<Observed<ValueT>>{obs}]() {
+                return !weak.expired();
+            }});
+        obs->attachEvent(eventId);
+    }
+
     template <typename ValueT>
     void listen(
         EventContext& eventContext,
@@ -67,21 +124,43 @@ namespace Nui
         });
     }
 
+    template <typename ValueT>
+    requires std::is_scalar_v<ValueT>
+    void listen(
+        EventContext& eventContext,
+        std::shared_ptr<Observed<ValueT>> const& obs,
+        std::function<void(ValueT)> onEvent)
+    {
+        return listen(eventContext, obs, [onEvent = std::move(onEvent)](ValueT value) {
+            onEvent(value);
+            return true;
+        });
+    }
+
     template <typename ValueT, typename FunctionT>
-    void listen(EventContext& eventContext, std::shared_ptr<Observed<ValueT>> const& obs, FunctionT onEvent)
+    requires(
+        (std::invocable<FunctionT, ValueT const&> || std::invocable<FunctionT, ValueT>) &&
+        !Detail::IsStdFunction<FunctionT>::value)
+    void listen(EventContext& eventContext, std::shared_ptr<Observed<ValueT>> const& obs, FunctionT&& onEvent)
     {
-        return listen(eventContext, obs, std::function(std::move(onEvent)));
+        return listen(eventContext, obs, std::function(std::forward<FunctionT>(onEvent)));
     }
 
     template <typename ValueT, typename FunctionT>
-    void listen(std::shared_ptr<Observed<ValueT>> const& obs, FunctionT onEvent)
+    requires(
+        (std::invocable<FunctionT, ValueT const&> || std::invocable<FunctionT, ValueT>) &&
+        !Detail::IsStdFunction<FunctionT>::value)
+    void listen(std::shared_ptr<Observed<ValueT>> const& obs, FunctionT&& onEvent)
     {
-        return listen(globalEventContext, obs, std::function(std::move(onEvent)));
+        return listen(globalEventContext, obs, std::function(std::forward<FunctionT>(onEvent)));
     }
 
     template <typename ValueT, typename FunctionT>
-    void listen(Observed<ValueT> const& obs, FunctionT onEvent)
+    requires(
+        (std::invocable<FunctionT, ValueT const&> || std::invocable<FunctionT, ValueT>) &&
+        !Detail::IsStdFunction<FunctionT>::value)
+    void listen(Observed<ValueT> const& obs, FunctionT&& onEvent)
     {
-        return listen(globalEventContext, obs, std::function(std::move(onEvent)));
+        return listen(globalEventContext, obs, std::function(std::forward<FunctionT>(onEvent)));
     }
 }
\ No newline at end of file
diff --git a/nui/include/nui/frontend/utility/val_conversion.hpp b/nui/include/nui/frontend/utility/val_conversion.hpp
index 8ddce54f..3db5b503 100644
--- a/nui/include/nui/frontend/utility/val_conversion.hpp
+++ b/nui/include/nui/frontend/utility/val_conversion.hpp
@@ -57,9 +57,9 @@ namespace Nui
     template <typename T>
     Nui::val convertToVal(std::map<std::string, T> const& map);
     template <typename T>
-    Nui::val convertToVal(std::unique_ptr<T> const& map);
+    Nui::val convertToVal(std::unique_ptr<T> const& ptr);
     template <typename T>
-    Nui::val convertToVal(std::shared_ptr<T> const& map);
+    Nui::val convertToVal(std::shared_ptr<T> const& ptr);
     inline Nui::val convertToVal(long long)
     {
         throw std::runtime_error("Cannot convert long long to val");
diff --git a/tools/inline_parser/test/CMakeLists.txt b/tools/inline_parser/test/CMakeLists.txt
index 0a4091e4..b7681562 100644
--- a/tools/inline_parser/test/CMakeLists.txt
+++ b/tools/inline_parser/test/CMakeLists.txt
@@ -1,6 +1,6 @@
 include(GoogleTest)
 
-find_package(Boost REQUIRED)
+find_package(Boost CONFIG REQUIRED)
 
 add_executable(inline_parser-tests
     tests.cpp