One gotcha that would bug me with Rust/WASM today is concurrency in the browser. You only get one thread per WASM binary AFAIK, and the way to compute in the ba

One gotcha that would bug me with Rust/WASM today is concurrency in the browser. You only get one thread per WASM binary AFAIK, and the way to compute in the background is to use a web worker. The abstraction libraries that are higher level than web_sys don't support transferable objects currently, so you'd have to write your web worker in web_sys directly to avoid needless data copying. It's pretty doable, and I've gotten started on a crate abstracting this part, but it's been a serious willpower blocker for me. One thread is pretty limiting for any web app today. As soon as you want to do something interesting, you're blocking the main thread.