Test of subscription watchers

sub_watch.cljs

(ns whatever.sub-test
  (:require [reagent.core :as r]
            [reagent.ratom :as ratom]
            [re-frame.core :as rf]))

(rf/reg-sub :test (fn [db] (:test db)))
(rf/reg-event-db :set-test (fn [db [_ newval]] (assoc db :test newval)))

(rf/reg-event-db :set-test-changed (fn [db [_ newval]] (assoc db :test-changed newval)))
(rf/reg-sub :test-changed (fn [db _] (:test-changed db)))

(rf/reg-event-db :change-d (fn [db [_ newd]]
                             (assoc-in db [:test :b 1 :d] newd)))

(defn dangerous-games []
  (let [changed (rf/subscribe [:test-changed])
        test (rf/subscribe [:test])
        _ (add-watch test :change
            (fn [_ _ _ _] (rf/dispatch [:set-test-changed true])))]
    [:div
     [:button {:on-click #(rf/dispatch [:set-test {:a 1 :b [{:c 3} {:d 4}]}])}
      "Set initial state"]
     [:button {:on-click #(rf/dispatch [:change-d (rand-int 10)])}
      "Change field in :test randomly"]
     [:button {:on-click #(rf/dispatch [:set-test-changed false])}
      "Reset :test-changed"]
     [:div ":test " (str @test)]
     [:div ":test-changed " (str @changed)]]))