Reagent ratom / reaction

reaction.cljs

(require '[promesa.core :as p]
         '[reagent.ratom :as ratom])

(def app-state (ratom/atom {:state-var-1 {:var-a 2
                                          :var-b 3}
                            :state-var-2 {:var-a 7
                                          :var-b 9}}))

(def app-var2a-reaction (ratom/make-reaction
                         #(get-in @app-state [:state-var-2 :var-a])))

(defn foo []
  (prn @app-var2a-reaction))

(ratom/track! foo)

(p/let [_ (p/delay 1000)]
  (swap! app-state update-in [:state-var-2 :var-a] inc)
  (p/delay 1000))