@ddrbt try this

(defn root []
  [:div
   (chart)
   [:h1 "hi"]])

this should work

[:ul
  (for [item @some-items]
    [:li {:key item} item])]

Oh sorry, the second message was a reply. I think cljsjs/recharts and rum have conflicting dependencies. Having recharts on the classpath prevented rum from mounting. Will investigate whether :exclusions could fix it