batch listener notifications

core/src/refx/hooks.cljs

@@ -28,7 +28,7 @@
  (react/useMemo
  (fn []
  [(fn [callback]
- (let [key (str "use-sub-" (swap! use-sub-counter inc))]
+ (let [key {:index (swap! use-sub-counter inc)}]
  (subs/-add-listener sub key callback)
  #(subs/-remove-listener sub key)))
  (fn []

core/src/refx/subs.cljc

@@ -76,6 +76,38 @@
  (doseq [[_ sub] @sub-cache]
  (dispose! sub)))
 
+(defonce ^:private listeners-state
+ (atom {:counter 0 :pending (sorted-map-by :index)}))
+
+(defn- invoke-listener
+ "This function is responsible for ensuring that signal listeners
+ (from DynamicSubs) are called before triggering regular listeners
+ (eg: added via use-sub hook). Listeners are triggered in the order they
+ were registered. This function ensures that one db update will only trigger
+ a single render."
+ [listener-key listener-fn]
+ (swap! listeners-state (fn [state]
+ (cond-> (update state :counter inc)
+ (not (signal? listener-key))
+ (update :pending assoc listener-key listener-fn))))
+
+ (when (signal? listener-key)
+ (listener-fn))
+
+ (interop/next-tick
+ (fn []
+ (let [listener-fns (atom nil)]
+ (swap! listeners-state (fn [state]
+ (let [{:keys [counter pending] :as new-state}
+ (update state :counter dec)]
+ (if (zero? counter)
+ (do
+ (reset! listener-fns pending)
+ (assoc new-state :pending (sorted-map-by :index)))
+ new-state))))
+ (doseq [[_ f] @listener-fns]
+ (f))))))
+
 (deftype Listeners [^:mutable listeners]
  Object
  (empty? [_] (empty? listeners))
@@ -84,8 +116,8 @@
  (remove [_ k]
  (set! listeners (dissoc listeners k)))
  (notify [_]
- (doseq [[_ f] listeners]
- (f))))
+ (doseq [[k f] listeners]
+ (invoke-listener k f))))
 
 (defn- make-listeners []
  (Listeners. nil))