react-native code-gen > Add a C++ only TurboModule example (for Android/iOS/macOS/Windows) (#35138)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/35138

Changelog:

[General][Added] - Add a C++ only TurboModule example (for Android/iOS/macOS/Windows)

react-native@0.69 introduced a new bridging layer to ease integration for pure C++ TurboModules using C++ std:: types directly instead of the lower level jsi:: types:
https://github.com/facebook/react-native/tree/v0.69.0/ReactCommon/react/bridging

This bridging layer can be used in JSI functions or more conveniently in C++ TurboModules.

Here is a example of an C++ only TurboModule which will work on Android and iOS and macOS/Windows (using microsoft/react-native-macos|windows) only using flow/TypeScript and standard C++ types.

C++ only TurboModules are very handy as they do not require to work with JSI APIs - instead std:: or custom C++ can by used.

Reviewed By: javache

Differential Revision: D39011736

fbshipit-source-id: 84c833d8540671fde8505f1aeb0265074b248730

packages/rn-tester/NativeCxxModuleExample/NativeCxxModuleExample_ConstantsStruct.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <react/bridging/Bridging.h>
+#include <optional>
+#include <string>
+
+namespace facebook::react {
+
+struct ConstantsStruct {
+  bool const1;
+  int32_t const2;
+  std::string const3;
+  bool operator==(const ConstantsStruct &other) const {
+    return const1 == other.const1 && const2 == other.const2 &&
+        const3 == other.const3;
+  }
+};
+
+template <>
+struct Bridging<ConstantsStruct> {
+  static jsi::Object toJs(jsi::Runtime &rt, const ConstantsStruct &value) {
+    auto result = facebook::jsi::Object(rt);
+    result.setProperty(rt, "const1", bridging::toJs(rt, value.const1));
+    result.setProperty(rt, "const2", bridging::toJs(rt, value.const2));
+    result.setProperty(rt, "const3", bridging::toJs(rt, value.const3));
+    return result;
+  }
+};
+
+} // namespace facebook::react