These are handy tricks, even in JS at scale, and I'd recommend their usage if you can (big if, business requirements come first for most of us). That said, I don't really buy into the no JS/purism movement for load/execution speed. For bite-sized apps or simple pages, sure. However, it's completely possible and not that hard to develop full-blown web application suites using full JS for everything (structure, style,…
If you put your app logic in something like Redux it'll work on server-side rendering, client-side rendering, and can be included in react-native down the line.
In the time the author re-wrote his app, I could have gotten the same benefits with SSR and ported it to react native. But yeah, javascript bad REEEE