Server components, Next application directory breaking emotion for styling, stricter rules for hooks, the compiler breaking change tracking libraries such as MobX removing the need for useMemo and similar. This is just off the top of my head in React land.
Unless maybe you want to start talking about CRDTs? But that's kind of niche, and CRDTs are actually an old conversation, one which started before React was first released. That should give you a sense at the pace of conversation for SPAs.
On an aside, SolidJS has been taking a huge momentum hit recently, I think the drop in downloads is a lagging indicator. It's not an easy space, I love SolidJS and recognize that Ryan Carniato likely took a career hit to work on Solid, but my bet is that Solid will fail to catch critical mass. Really sad as I love the Solid experience.
Nope, not using.
> Next application directory breaking emotion for styling
I'm not even sure what this is.
> stricter rules for hooks
I've always been strict with the code, no changes have been required.
> the compiler
The compiler is still in beta, I've not even tried it, let alone let it near production code. I'm not that excited by it tbh.
So you've pretty much confirmed what I said. None of these things were that important to jump on.
Code written with the react compiler in mind will inevitably be MUCH slower without the compiler, as its not going to manually add any memoization. Likely to the point where its not going to be usable without it.