Curious layman here (no web dev experience). I thought the main selling point of reactive programming was that it abstracted away the need to manage state. What problems, then, does a state management library solve in a reactive framework?
Rethinking reactivity
https://www.youtube.com/watch?v=AdNJ3fydeao
He goes over the history of spreadsheets, reactive programming, and dunks on react.
It answers my question only tangentially, because it doesn’t touch state management per se. The key point was, what’s the fuss about React SM and why it must be explicit in it. The video basically says that it is a nonsense which may and should be avoided. I agree, and so still don’t get what ggp is talking about.
If you have a component A, which renders component B, which in turn renders component C, without a state management library you'd have to pass state from A to B to C (this is often called prop drilling). The longer the call stack, the more irritating this becomes.
State management libraries allow component C and component A to modify, and subscribe to a shared state store. Redux et al. are effectively the reactive version of global variables.
Any discussion that doesn't revolve around a difference between the two is akin to suggesting re-implementing a standard library call for literally no reason.
He seemed to be wondering why you need a state management solution in the first place. If he had asked why people prefer Zustand, or Redux, or Recoil over React's built in context api then I would have replied accordingly.
I was largely expounding upon the linked article's first list item under the heading "The problems global state management libraries need to solve". The first item in that list begins with:
> Ability to read stored state from anywhere in the component tree. This is the most basic function of a state management library. It allows developers to persist their state in memory, and avoid the issues prop drilling has at scale.
I would argue that the primary function of state management libraries is still sharing state between components. Third-party libraries might expose a more performant, simpler, or more intuitive api, but that's still their primary purpose. Analogously, if a non-compiler developer asked why programming languages need memory management, you wouldn't delve into the differences between reference counting and tracing garbage collection.