What it appears to take to re-render the React tree when Figwheel reloads.

rerender.cljs

;; Re-render when Figwheel reloads.
(gevents/listen js/document.body
                "figwheel.js-reload"
                (fn []
                  (let [root-component (om-next/app-root (compassus/get-reconciler a))]
                    (letfn [(js-vals [o]
                              (map #(aget o %) (js-keys o)))
                            ;; Finds the children of a React internal instance of a component.
                            ;; That could be a single _renderedComponent or several
                            ;; _renderedChildren.
                            (children [ic]
                              (or (some-> (.-_renderedComponent ic) vector)
                                  (js-vals (.-_renderedChildren ic))))
                            (descendant-components [c]
                              ;; Walk the tree finding tall of the descendent internal instances...
                              (->> (tree-seq #(seq (children %)) children (.-_reactInternalInstance c))
                                   ;; ...map to the public component instances...
                                   (map #(.-_instance %))
                                   ;; ...and remove the nils, which are from DOM nodes.
                                   (remove nil?)))]
                      (doseq [c (descendant-components root-component)]
                        (.forceUpdate c))))))