On algorithmic code, idiomatic Rust + WASM is often about 10 to 40 times faster than idiomatic JS. The problem however is that each call between WASM and JS has

On algorithmic code, idiomatic Rust + WASM is often about 10 to 40 times faster than idiomatic JS. The problem however is that each call between WASM and JS has a hefty cost of about 750ns. So your algorithm needs to be doing a significant amount of independent calculations before you will see these performance differences.