Function useEventSource

apps/webapp/app/hooks/useEventSource.tsx:15–43

(
  url: string | URL,
  { event = "message", init, disabled }: EventSourceOptions = {}
)

 * @returns The last event received from the server
 */
export function useEventSource(
  url: string | URL,
  { event = "message", init, disabled }: EventSourceOptions = {}
) {
  const [data, setData] = useState<string | null>(null);

  useEffect(() => {
    if (disabled) {
      return;
    }

    const eventSource = new EventSource(url, init);
    eventSource.addEventListener(event ?? "message", handler);

    // rest data if dependencies change
    setData(null);

    function handler(event: MessageEvent) {
      setData(event.data || "UNKNOWN_EVENT_DATA");
    }

    return () => {
      eventSource.removeEventListener(event ?? "message", handler);
      eventSource.close();
    };
  }, [url, event, init, disabled]);

  return data;
}