Clojurians Log v2

Is it bad practice to subscribe from inside a computation function in reg-sub? I’m trying to figure out how to materialize relationships but I don’t have the nested data until the computation function.

You probably want reg-sub-raw then

@limix maybe signal functions? https://github.com/day8/re-frame/blob/2965ffeda9b8f3b687e2c3e0ba9a62e7fe64c0bb/src/re_frame/core.cljc#L201

new blog post on re-frame and firebase: https://widdindustries.com/clojurescript-firebase-simple/ which talks about signal functions and limited use of re-frame app-db. feedback welcome 🙂

hi, in some cases i can see in traces that subscription run in each tick, even if there are no changes in app-db, why it might happen ? so it seems like subscription is broken and it just run on each tick

hm interesting if i hot reload and clear cache it won't be run anymore

ok it seems like subscription is used in event handler

and at some point its broken and started to run on each tick

It's not broken, it's just not cached.

but why is it run on each tick ?

I don't know what your code is exactly so I cannot answer that. Perhaps that event handler is called on each tick, perhaps something else.

Alternatively, you might be right and there might be some bug. But again, I can't say anything without having an MRE.

yes sure, thanks

I also often need a snack before debugging a problem 😀

I already had breakfast. :)

Huh, it's been quite some time since I heard "MRE" used in a meal-related context.

Hey Guys! Happy Fried-day! I was facing an conflict issue in my project and I'd like to have your input on the way I resolved it. # The problem In my project I had the tim-v interceptor registered globally:

(re-frame/reg-global-interceptor trim-v)

(rf/reg-event-fx
 (fn [_ [prop]]
   {:dispatch {::some-event prop}}))

(rf/reg-event-fx
 (fn [_ [_ event-type]]
   {::keyboard-event {:event-type event-type}}))

(defonce ns-whitelist #{"foo" "bar"})

(defn- event-is-whitelisted
  "Returns true if the event is in the namespace white list"
  [whitelist context]
  (contains? whitelist (-> context
                           (get-coeffect :original-event)
                           first
                           namespace
                           (split #"[\./]")
                           first)))

(defn- get-whitelisted-int
  "Executes the interceptor only if the scope falls in the whitelist"
  [whitelist interceptor]
  (let [{:keys [id before after]} interceptor
        whitelisted (partial event-is-whitelisted whitelist)]
    (->interceptor
      :id id
      :before #(if (and (some? before) (whitelisted %)) (before %) %)
      :after #(if (and (some? after) (whitelisted %)) (after %) %))))

(defn- reg-global-interceptor
  "Delimits the scope of the interceptor"
  [interceptor]
  (re-frame/reg-global-interceptor (get-whitelisted-int ns-whitelist interceptor)))

In this code block:

(rf/reg-event-fx
 (fn [_ [_ event-type]]
   {::keyboard-event {:event-type event-type}}))

Because this code is from re-pressed which is an external project/dependency: https://github.com/gadfly361/re-pressed

I see. In general, I don't think that it's a good idea to use event-modifying interceptors globally. In my projects, I have a custom versions of reg-event-* functions that inject that interceptor automatically. kee-frame does it as well, for example.

Good point! This means that my problem is due to a bad pattern/design. Maybe it'd be good to mention exactly what you just wrote in re-frame's documentation about interceptors? :)

Perhaps - you can always open an issue an submit a PR. :)

But I would steal those lovely words from you 😄 I'll try, thank you @p-himik!!

I consider all my community activities to be under the CC license. :) NP!