2 files changed, 12 insertions, 0 deletions
diff --git a/src/platform/web/CMakeLists.txt b/src/platform/web/CMakeLists.txt
index 1287f85a..0a9bd6dd 100644
--- a/src/platform/web/CMakeLists.txt
+++ b/src/platform/web/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_library(CruPlatformBaseWeb
+	JsUtility.cpp
 	Resource.cpp
 )
 
diff --git a/src/platform/web/JsUtility.cpp b/src/platform/web/JsUtility.cpp
new file mode 100644
index 00000000..b426bbda
--- /dev/null
+++ b/src/platform/web/JsUtility.cpp
@@ -0,0 +1,11 @@
+#include "cru/platform/web/JsUtility.h"
+
+namespace cru::platform::web {
+bool IsNotNullAndInstanceOf(const emscripten::val& value, const emscripten::val& type) {
+  return !value.isNull() && !type.isNull() && value.instanceof(type);
+}
+
+bool IsNotNullAndInstanceOf(const emscripten::val& value, const char* global_type) {
+  return IsNotNullAndInstanceOf(value, emscripten::val::global(global_type));
+}
+}