there's a related issue for derived atom and watchers https://github.com/tonsky/rum/issues/94

Thanks :) i did see this, but my question is a bit broader - would the pattern I'm using be considered as intended, or should I be doing something entirely different? I find this particularly when dealing with collections where I need to iterate through the collection to embed their components, but then if I just react on the collection itself, any change (obviously) rerenders the entire parent component

@U050CLJ53 The pattern you describe is known (part of optimization of a component) and the issue you describe is also known as @U0FR82FU1 said above.

Personally I use a hook that does the cleanup

Something along the lines: https://github.com/g7s/rum/blob/hooks/src/rum/core.cljs#L572

@UKQS17P3L great, thanks for the feedback - use-derived-atom looks interesting - is this in a fork?

Yes it is in a fork that I had made long ago.

ah, ok - I see the current rum code has:

(defn use-reducer [reducer-fn initial-value]
  [initial-value reducer-fn])

(defn use-effect!
  ([setup-fn])
  ([setup-fn deps]))

(defn use-callback
  ([callback] callback)
  ([callback deps] callback))

probably in prep for moving away from React?

I guess a similar effect might be achieved with a mixin if there's a registry of derived atoms against a component?

Yeah exactly you can do that with a mixin as you describe