[Chartjs]-Clojurescript/Reagent/Chart.js – Reagent life cycle – chart.update()

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The usual pattern you follow in this case is to wrap the stateful/mutable object in a React component and use React’s lifecycle methods.

The approach is described in detail in re-frame‘s Using-Stateful-JS-Component but this is how I tend to do it with D3:

(defn graph-render [graph-attrs graph-data]
  ;; return hiccup for the graph here
  (let [width (:width graph-attrs)
        height (:height graph-attrs)]
    [:svg {:width width :height height}
     [:g.graph]]))

(defn graph-component [graph-attrs graph-data]
  (r/create-class
   {:display-name "graph"
    :reagent-render graph-render
    :component-did-update (fn [this]
                            (let [[_ graph-attrs graph-data] (r/argv this)]
                              (update! graph-attrs graph-data)))
    :component-did-mount (fn [this]
                           (let [[_ graph-attrs graph-data] (r/argv this)]
                             (init! graph-attrs graph-data)))}))

(defn container []
  [:div {:id "graph-container"}
   [graph-component
    @graph-attrs-ratom
    @graph-data-ratom]])

It is important to keep the outer/inner combination because React won’t populate its props correctly otherwise.

Another thing to be carefully of is the return of the reagent/argv vector, which, as you can see, contains the props after the first item. I have seen (reagent/props comp) in the wiki page above but I have never tried it myself.

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