[pmarcelll]

I haven't seen it mentioned, but memory usage might also be better, and I have a good real-world example to show why it still matters in 2020: we use Jira to manage our software projects and our team's project manager uses a newish MacBook Air with 8GB of RAM. Jira is written in React and a single page for a ticket can easily eat 150+ MB of memory (it's even more for Jira boards). Our PM regularly complains about the slowness of his machine and I think Jira is a big contributing factor. I don't think much of the memory is used for presentation (so it might not be React's fault), but rather for business logic processing a large amount of data. And IIRC calling a simple `filter()` on a JS array creates a new array for the operation while Rust uses iterators.

[akiselev]

I regularly slow to a crawl on a 32gb Mac Book Pro requiring a reboot because it starts swapping thanks to Chrome tabs, electron apps/VSCode, and webpack/cargo/whatever to the point that running cat on a file takes 5-10 seconds. All it takes is a little memory exhaustion for the kernel to pick a process for swap (iterm and its children? why, thank you kernel!) and drive it into the ground. With Chrome it might swap just a single tab process or it might swap the rendering process

I don't know why it seems React apps are some of the worst offenders, but I think it has to do with hooks injecting context components everywhere (at least that's what it looked like last time I popped open React dev tools). I'm guessing that out of tree state tracking is particularly memory intensive.