[nicoburns]

> V8 is so good at optimizing code, it's usually possible to reach similar performance in JS.

It often is, but unless your code is purely numerical (in which case V8 is fast by default) you have write very awkward code to make JavaScript fast. On the other hand you can often transliterate JS code 1:1 into Rust and it'll be 10x faster.

[masklinn]

That is well demonstrated by the sourcemap events from 2018: Mozilla replaced part of the source-map JS library by a straightforward Rust rewrite compiled to WASM, yielding a 5.9x speed improvement (with much less variance to boot) (Oxidising Source Maps with Rust and WebAssembly).

mraleph then went through a pretty epic bout of algorithmic improvement and engine-specific optimisations, reaching not quite parity with the rust/wasm version but close (Maybe you don’t need Rust and WASM to speed up JS).

Nick Fitzgerald was then able to relatively easily add the algorithmic improvements to the WASM version for an other 3x gain (~10x total from the original) (Speed Without Wizardry).

[cesarb]

To save some searching, the three referenced articles seem to be:

- Oxidising Source Maps with Rust and WebAssembly: https://hacks.mozilla.org/2018/01/oxidizing-source-maps-with...

- Maybe you don’t need Rust and WASM to speed up JS: https://mrale.ph/blog/2018/02/03/maybe-you-dont-need-rust-to...

- Speed Without Wizardry: https://fitzgeraldnick.com/2018/02/26/speed-without-wizardry...