To see results, show "vanillajs-1" and "wasm-bindgen", then hide everything else. WASM is about 6% slower, 18% longer startup, and 66% more memory usage.

Note this is a UI benchmark so the results are overwhelmingly dominated by DOM interop. Things should improve if the WASM interface types proposal ever lands.

I think the electron memory usage comes down to the massive HTML spec and bloated old browser codebases. It's not JS. Node+V8 doesn't have nearly the memory usage of Chrome+V8.

Browsers are often able to defer parsing of JS functions until they're called, so dead JS code doesn't cost much in parsing time.

In JS first run goes through an interpreter (without a delay for compilation/optimization), so JS has a pretty low latency for initial execution.

JS is relatively easy to split into pieces and lazy load (there are various bundlers that support "chunking"), and not loading code is faster than fastest parsers. WASM could theoretically do that too, but current languages and tooling are more geared towards monolithic executables. For UI, where time to interactive matters most, JS will likely do a better than a big blob of WASM.

WASM still needs to call out to JS for DOM interactions, so if your UI is DOM-based, you'll need a bunch of JS anyway, and have JS<>WASM communication overhead.

You sure? Just figuring out what to call us going to typically require full parsing to find identifiers, scoping, etc.