it's only used for setting the default ws-url as far as I can see
(defn default-ws-url []
(when (exists? (.-location js/window))
(let [host-and-port (.-host js/window.location)
ssl? (re-find #"^https" (.-origin js/window.location))]
(str (if ssl? "wss" "ws") "://" host-and-port "/graphql-ws"))))
Code could where the function is used could be changes to only execute when needed.