I'm sure I've read about this in the re-frame docs or some other place, but can't find it. Trying to figure out how to do "nested" subscriptions (one subscription is for :setup in db, next one for -> :setup :password for example)

Sure, I do that all the time. You can use the output from one subscription as the input to another. See the comments in this file for detailed docs: https://github.com/Day8/re-frame/blob/master/examples/todomvc/src/todomvc/subs.cljs

hah, fun, I just came across this and came up with this, based on that very file:

(reg-sub
  :setup
  (fn-traced [db _]
             (:setup db)))

(reg-sub
  :setup-password
  (fn-traced [_ _]
             (:password @(subscribe [:setup]))))

Thanks a lot @manutter51 🙂

hm, one difference, I put @(subscribe) (with @) but the subs.cljs doesn't have that. Don't you need to deref it to get the actual value?

I wouldn’t recommend putting a subscribe inside a subscription handler, there’s a better way.

ah, alright. I got the inspiration for that from here https://github.com/Day8/re-frame/blob/master/examples/todomvc/src/todomvc/subs.cljs#L60-L83

ah, further down is some syntactic sugar https://github.com/Day8/re-frame/blob/master/examples/todomvc/src/todomvc/subs.cljs#L135-L144

(reg-sub
 :setup
 (fn-traced [db _]
   (:setup db)))

(reg-sub
 :password 
 :<- [:setup]
 (fn [setup]
   (:password setup)))

Yeah, makes sense. Thanks again 🙂

Heh, yeah, you got to it while I was trying to type out the example 🙂

indeed. None the less, thanks for the pointers!

:thumbsup:

is there a similar pattern for reg-event-db? (basically nesting them)

You can use reg-event-fx and return a map with keys for :dispatch (a single new event to dispatch) or :dispatch-n (a vector of events to dispatch), or :dispatch-later (a tuple of event-to-dispatch + time-to-delay, I forget which order they’re in)

:reg-event-db is a simplification of :reg-event-fx, for the most common use-case.

@manutter51 I see. Might be able to work something out with that. Thanks

Be sure to read the docs for reg-event-fx — it takes slightly different args and returns a different value than :reg-event-db

Hey everybody, since re-frame is mostly in .cljc files I have been trying to exercise it with the Clojure REPL. This has lead to problems so I've opened an issue on re-frame's github. If any of you have any insight please feel free to comment on it. https://github.com/Day8/re-frame/issues/522