Nicely grouped transaction logging in JS Console for Om apps

start.cljs

(ns app
  (:require [om.core :as om :include-macros true]))
            
(defn log-tx [tx-data root-cursor]
  (let [{:keys [path old-value new-value]} tx-data
        c js/console]
    (doto c (.group (str "TRANSACTION " path)) (.groupCollapsed "OLD"))
    (prn (pr-str old-value))
    (doto c (.groupEnd) (.group "NEW"))
    (prn (pr-str new-value))
    (doto c (.groupEnd) (.groupEnd))))

(defn render
  [root state app debug?]
  (when debug?
    (enable-console-print!))
  (om/root app
           state
           (cond-> {:target root
                    :shared {:config (assoc (:config state) :debug? debug?)}}
                   debug? (assoc :tx-listen log-tx))))

;; (render (.getElementById "app") {:config {...} ...} app-component :debug)