Yeah, MobX is a great tool for fine-grained reactivity + managing state outside UI tree. I haven't seen anyone try relational querying in MobX, would be curious if that's a thing.

We've built an architecture somewhat like this where we're using MobX objects in the frontend (a graph of the db objects effectively) that's patched by subscriptions to tables via hasura. So we effectively have all the data on hand locally all the time and use the reactivity on top of that.

We actually played around with sqlite in wasm because I really really miss having a real relational db in the frontend. We decided that there was just a few too many unknowns to proceed further with the idea. Initially we were using indexdb as a frontend cache but dropped that since without adding more layers to it it doesn't provide much value.

(Also played around with using Solid's direct mobx -> jsx library without having react inbetween https://github.com/ryansolid/mobx-jsx but, again, too much unproven tech to build on).

The work you're doing here is super exciting. The developer experience of what we currently have is pretty nice and I can definitely see your model working out well in the future.