Define Custom Elements in ClojureScript

custom-elements.cljs

;; Solution based on https://stackoverflow.com/questions/50295703/create-custom-elements-v1-in-es5-not-es6
(defn define-element! [name on-connect]
  (let [my-el (fn [] (this-as this (.construct js/Reflect js/HTMLElement #js [] (.-constructor this))))
        _     (set! (.. my-el -prototype) (.create js/Object (.-prototype js/HTMLElement)))
        _     (set! (.. my-el -prototype -constructor) my-el)
        _     (.setPrototypeOf js/Object my-el js/HTMLElement)
        _     (set! (.. my-el -prototype -connectedCallback) on-connect)]
    (.define js/customElements name my-el)))

(define-element! :my-element #(.log js/console "hi!"))