[Enhancement]: reg-event-fx :fx shorthand

[sirmspencer]

What do you suggest?

Since any effect in the returned map for reg-event-fx can be added to the :fx effect, could you consider overloading reg-event-fx to take just the :fx vector as a response?

(reg-event-fx
  :example
  (fn []
    {:db {}
     :dispatch []}))

Can be written as

(reg-event-fx
  :example
  (fn []
    {:fx [[:db {}]
          [:dispatch []]]}))

So an overloaded reg-event-fx could accept this as a response, and assume :fx.

(reg-event-fx
  :example
  (fn []
    [[:db {}]
     [:dispatch []]]))

[mike-thompson-day8]

There's nothing wrong with the idea, but I won't implement it. Closing.

Why?

• it is generally better if there is only one way of doing things (Eg. I regret putting the syntax sugar for subscriptions into re-frame core)
• there's already a couple of ways you can implement this choice yourself already (in not much more than 10 lines of code):
  • write and use an interceptor
  • write and use your own version of reg-event-fx

[mike-thompson-day8]

BTW, here's what I mean by an interceptor that does the job (untested):

(def wrap-effects
  (re-frame.core/->interceptor
   :id    :wrap-effects
   :after (fn [context]
            (assoc context :effects {:fx (:effects context)}))))    ;; <-- wrap existing effects in a map like this {:fx  <existing>}

Then, write your own version of reg-effects-fx to install this wrap-effects interceptor immediately before the event handler is called (my code below is based on existing code for reg-effects-fx here)

(defn reg-event-fx2       ;; <-- my new name
  ([id handler]
   (reg-event-fx id nil handler))
  ([id interceptors handler]                                                                          ;; vvvvvvvvvvvvv
   (events/register id [cofx/inject-db fx/do-fx std-interceptors/inject-global-interceptors interceptors wrap-effects (fx-handler->interceptor handler)])))
                                                                                                      ;; ^^^^^^^^^^^^^

(also untested)

Notice the use/placement of wrap-effects

[sirmspencer]

That's neat, I will try that.

"I regret putting the syntax sugar for subscriptions into re-frame core". I just saw that expansion of syntactic sugar in 1.3 and thought this idea was in line with that. It's interesting to hear you already regret that change.