Comment by Flux159
Followup comment about Apple disallowing JIT - will need to confirm if JSC is allowed to JIT or only inside of a webview. I was able to get JSC + wgpu-native rendering in an iOS build, but would need to confirm if it can pass app review.
There's 2 other performance things that you can do by controlling the runtime though - add special perf methods (which I did for draco decoding - there is currently one __mystralNativeDecodeDracoAsync API that is non standard), but the docs clearly lay out that you should feature gate it if you're going to use it so you don't break web builds: https://mystralengine.github.io/mystralnative/docs/api/nativ...
The other thing is more experimental - writing an AOT compiler for a subset of Typescript to convert it into C++ then just compile your code ("MystralScript") - this would be similar to Unity's C# AOT compiler and kinda be it's own separate project, but there is some prior work with porffor, AssemblyScript, and Static Hermes here, so it's not completely just a research project.
Is AssemblyScript good for games though? last I checked it lacks too much features for game-code coming directly from TS but might be better now? No idea how well static hermes behaves today (but probably far better due to RN heritage).
I've been down the TS->C++ road a few times myself and the big issue often comes up with how "strict" you can keep your TS code for real-life games as well as how slow/messy the official TS compiler has been (and real-life taking time from efforts).
It's better now, but I think one should probably directly target the GO port of the TS compiler (both for performance and go being a slightly stricter language probably better suited for compilers).
I guess, the point is that the TS->C++ compilation thing is potentially a rabbit-hole, theoretically not too bad, but TS has moved quickly and been hard to keep up with without using the official compiler, and even then a "game-oriented" typescript mode wants to have a slightly different semantic model from the official one so you need either a mapping over the regular type-inference engine, a separate on or a parallell one.
Mapping regular TS to "game-variants", the biggest issue is how to handle numbers efficiently, even if you go full-double there is a need to have conversion-point checking everywhere doubles go into unions with any other type (meaning you need boxing or a "fatter" union struct). And that's not even accounting for any vector-type accelerations.