[prideout]

> a C++ object will become a garbage-collected JS object.

This sounds great for ease-of-use and cross-language binding. But, there's a downside with respect to performance. With Emscripten, you never see any GC events show up in the profiler.

[yuri91]

Indeed, as I said it can be a downside.

What we usually suggest is to compile most of the application to Wasm (which is also the default), and move the parts that most interact with the outside world to JS.

This can actually result in a speedup if it avoids multiple back-and-forths between JS and Wasm, which is common if you use a Browser/JS api from Wasm.