d3.cljs

(defn render-squares
  [component props]
  (let [svg (-> js/d3 (.select (dom/node component)))
        data (clj->js (:squares props))
        selection (-> svg
                    (.selectAll "rect")
                    (.data data (fn [d] (.-id d))))]
    (-> (.enter selection)
      (.append "rect")
      (.style "fill" (fn [d] (.-color d)))
      (.attr "x" "0")
      (.attr "y" "0")
      .transition
      (.attr "x" (fn [d] (.-x d)))
      (.attr "y" (fn [d] (.-y d)))
      (.attr "width" (fn [d] (.-size d)))
      (.attr "height" (fn [d] (.-size d))))
    (-> selection
      .exit
      .transition
      (.style "opacity" "0")
      .remove)
    false))