core.cljs

(def editor-state (atom #{:value "foobaar"}))
(defn on-plain-text-change [& args] (println args))
(rum/defc PlainText < rum/reactive
  []
  (js/React.createElement js/Slate.Editor
                          #js {:placeholder "enter enter enter"
                               :value (:value (rum/react editor-state))}))

(rum/defc plain-text
  []
  (js/React.createElement PlainText))

(defn MyPlainText [props context updater]
  (this-as this
    (js/React.Component.call this props context updater)
    (js/goog.object.set this :state (js-obj :value (js/Slate.Plain.deserialize "foo")))
    this))

(js/goog.object.extend (.-prototype MyPlainText)
                       js/React.Component.prototype
                       #js {:render (fn []
                                      (this-as this
                                        (js/React.createElement js/Slate.Editor
                                                                #js {:placeholder "bar"
                                                                     :value this.state.value})))})

(set! (.. MyPlainText -prototype -constructor) MyPlainText)
(rum/defc my-plain-text
  []
  (js/React.createElement MyPlainText))