step4-2.cljs

(defui ElementList
  static om/Ident
  (ident [this {:keys [id]}]
    [:list/by-id id])
  static om/IQuery
  (query [this]
    [:id {:elements (om/get-query Element)}])
  Object
  (on-drag-start [this element]
    (om/transact! this `[(element/drag {:from ~(om/get-ident this) :element ~element}) :app/lists]))
  (render [this]
    (let [{:keys [id elements]} (om/props this)
          {:keys [dragging]} (om/get-computed this)]
      (dom/div nil
               (dom/h4 nil (str "List with id : " id))
               (dom/ul #js {:onDragEnter (fn [e]
                                           (.preventDefault e))
                            :onDragOver  (fn [e]
                                           (set! (.. e -dataTransfer -dropEffect) "move")
                                           (.preventDefault e))
                            :onDrop      (fn [e]
                                           (.preventDefault e)

                                           )}
                       (map (fn [el]
                              (element (om/computed el {:on-drag-start #(.on-drag-start this %)})))
                            elements))))))