Sorry for late reply Datomic team have come out with an improved story for local dev: https://docs.datomic.com/cloud/dev-local.html but I'd still it's a bit much to take in all at once, I'd recommend using https://github.com/replikativ/datahike on the JVM, I don't think it's good enough for production (at least the write speeds were slow when I tried) but it does aim to be API compatible with Datomic so should be able to swap out for true Datomic before production
And in CLJS there's https://github.com/tonsky/datascript
there are a bunch of others I just found those easy to play with in dev to get an idea of how things work
I listened to the clojurescript podcast about Fulcro, it sounds like guard rails pro is going to be really cool, I'm not keen on guard rails in its current form and use clj-kondo instead but it's "type checking" isn't great
he said it would be able to report via LSP server and some other mechanisms like web interface etc I'm guessing a bit but to me it sounds like you'll be able to annotate your functions with specs like current guardrails then have those constraints reviewed statically which would be big for specification I think
Not I'd want to use it most of the time, clj-kondo is just enough static checking for me, but I think it'll probably have big returns when/if the code base evolves beyond the ability to keep it all in your own head and you have to start bashing off the guard rails