Clojurians Log v2

reading the channel makes me question about how I use reagent and re-frame.. this is a typical view function from my app

(defn main-panel []
  (let [fund-filters-loaded? @(rf/subscribe [:fund.filters.subs/loaded])
        logged-profile @(rf/subscribe [:logged-profile])]
    [:<>
     [chart]
     (if fund-filters-loaded?
       [:<>
        [filters {:suspended-enabled? false
                  :custom-filter #(custom-filter logged-profile)}]
        [fund-list callback]]
       [:div "loading..."])]))

this is a form-1 component according to reagent documentation

my question is, should it be form-2 and return a function instead?

@wvelezva what you wrote works. re-frame caches subscriptions, so when your component re-renders it will get the same subscription value every time

the reason you'd use a form-2 is it if you wanted something to only run on component mount (first render)

e.g.:

(defn my-component []
  (let [count (r/atom 0)]
    [:button {:on-click #(swap! count inc)} @count]))

☝️ that would re-create the count atom every render, so it would always say "0"

(defn my-component []
  (let [count (r/atom 0)]
    (fn []
      [:button {:on-click #(swap! count inc)} @count])))

I understand, and that is not desirable so in my case with the subscriptions?

and only make the dereference in the inner fn?

(defn main-panel []
  (let [fund-filters-loaded? (rf/subscribe [:fund.filters.subs/loaded])
        logged-profile (rf/subscribe [:logged-profile])]
    (fn []
      [:<>
       [chart]
       (if @fund-filters-loaded?
         [:<>
          [filters {:suspended-enabled? false
                    :custom-filter #(custom-filter @logged-profile)}]
          [fund-list callback]]
         [:div "loading..."])])))

like I said above, you can use either a form-1 or form-2 because re-frame caches subscriptions

(rf/subscribe [:fund.filters.subs/loaded]) will return the same thing every time

it will only create the subscription once

so you may use it in a form-1

so is a matter of taste?

use form-2 if and only if, you are dealing with local states i.e using reagent to manage form state

yes it's a matter of taste

other than that its preferred to use form 1

form 1 makes component simpler

since it only does one thing, renders component

😌

thanks a lot!

how ever, if you still want to use form 1 component while managing local state

you can do that

there is a trick

I’m all ears….

(defn simple-form [args]
  (reagent/with-let
   [state (reagent/atom {:username ""})]
   [:form
    [:input {:type :text
             :placeholder :username
             :on-change #(swap! state assoc :username (-> % .-target .-value))
             :value (:username @state)}]]))

the trick is to wrap the component with with-let function

and voila, no more form-2

the code I inherited had those with-let plus the subscriptions, when I started learning I didn’t see any difference between with-let and the “simple” let so I adopted that style

thanks @lilactown and @vishal.gautam

Anyone know if it is possible to configure the React Dev Tools to highlight updates to Reagent components? 🤞