(defn form [init-state spec]
  {:will-mount
   (fn [state]
     (let [local-state (atom init-state)
           validate #(let [v @local-state
                           valid? (s/valid? spec v)]
                       {:valid? valid?
                        :errors (when-not valid? (s/explain-data spec v))})
           validation (atom (validate))
           component (:rum/react-component state)]
       (add-watch local-state spec
                  (fn [_ _ ost nst]
                    (when (not= ost nst)
                      (reset! validation (validate)))
                    (rum/request-render component)))
       (assoc state
         :form/state local-state
         :form/validation validation)))})