Convert an image url to a data URI without canvas

image-url-to-data-uri.cljs

(require '[ajax.protocols :as pr])

;; effecting with re-frame-http-fx
{:http-xhrio {,,,
              :response-format {:content-type "image/png"
                                :description "PNG image"
                                :read pr/-body
                                :type :arraybuffer}
              :on-success [::my-handler]}

(rf/reg-event-db
 ::my-handler
  (fn [db [_ response]]
    (assoc db :thing (->> response
                          (js/Uint8Array.)
                          (js/String.fromCharCode.apply nil)
                          (js/btoa)
                          (str "data:image/png;base64,")))))