called-twice.cljs

(defn read [{:keys [state ast]} key params]
  (println "called")
  {:value (get @state key :not-found)})

((om/parser {:read read}) {:state (atom {})} '[:foo])

;; output:
;; called

(def reconciler
  (om/reconciler
   {:state {:transactions []}
    :parser (om/parser {:read read})}))

(om/transact! reconciler '[:foo])

;; output:
;; called
;; called