Types (interface contracts) are already easily sharable with an IDL and code generation. There's no need to stick to a common programming language to share types.
I'm highly skeptical of code sharing for other scenarios, and rarely (never) have seen the effort worth the payoff.
See my other comment above, but I was able to share basically everything that was not UI code. Types, request hooks, utils, configs/constants. Probably about 60% of the app, and you wouldn’t want to share UI code anyway because web and Native are so different.
I'm highly skeptical of code sharing for other scenarios, and rarely (never) have seen the effort worth the payoff.
- https://protobuf.dev/
- https://smithy.io/2.0/