Support for Pure C++ TurboModules with Swift AppDelegate in React Native 0.78

[jerryseigle]

I’m using React Native 0.78 and trying to build a TurboModule in pure C++ so I can share the same code on both iOS and Android (no platform-specific code).

Android setup works fine, but I’m running into issues on iOS since I’m using the default AppDelegate.swift from the new architecture.
• Is there a way to use pure C++ TurboModules with Swift AppDelegate in 0.78?
• Do I need to switch to Obj-C for registration, or is there a workaround?
• Is there a roadmap or plan for better Swift+C++ TurboModule support?

[cortinico]

Support for what you're asking for is coming in React Native 0.79 in the coming days/weeks, so we ask you to wait a little for it. There will be an announcement in the release blogpost.

@cipolleschi can also tell you more about it.

[jerryseigle]

Yes I just tested with the beta version and it's working nicely. I did notice a very minor bug and it may not be a bug but I notice that if I start metro and then I run the command from Mac terminal npx react-native run-ios it will start the project without problems. However with metro running if I just press the play button to start the project it seem that any turbo module that needs to run on the main thread does not start right off and app crash. We have to start the project using the terminal command

[cipolleschi]

Hi @jerryseigle, thanks for the question, but it does not really makes sense... 🤔
npx react-native run-ios under the hood does:

• yarn start
• xcodebuild build
• install and run

so it is equivalent to starting metro manually and pressing play on Xcode.

There might be other things that are causing the issue you are seeing. it could be a race condition during reload, perhaps.

[shamilovtim]

@cipolleschi in the the time I've been in the RN world I have found there to be significant differences in outcome between CLI runs because they use the xcode cli vs. IDE builds. I've found CLI builds tend to bring out more flakes in the various frameworks, scripts and codegen than IDE builds. I would say that has also been the case with most colleagues who use the framework.