GCTC-NTGC / TalentCloud

export function useResource<T>(

  endpoint: string,

  initialValue: T,

  overrides?: {

    parseResponse?: (response: Json) => T; // Defaults to the identity function.

    skipInitialFetch?: boolean; // Defaults to false. Override if you want to keep the initialValue until refresh is called manually.

  },

): {

  value: T;

  status: ResourceStatus;

  error: undefined | Error | FetchError;

  update: (newValue: T) => void;

  refresh: () => void;

} {

  const internalParseResponse = overrides?.parseResponse ?? identity;

  const skipInitialFetch = overrides?.skipInitialFetch === true;

  const valueRef = useRef(initialValue);

  const { error, status, reload, run } = useFetch(

    endpoint,

    fetchParameters("GET"),

    {

      onResolve: (data) => {

        valueRef.current = internalParseResponse(data);

      },

      initialValue: null, // Setting this prevents fetch from happening on first render. (We call it later if necessary.)

    },

  );

  const refresh = reload;

  const update = (newValue: T): void => run(fetchParameters("PUT", newValue));

  // Despite the usual useEffect guidelines, this should only run on first render or when endpoint changes.

  // Changing skipInitialFetch after the first render should not cause a refresh.

  useEffect(() => {

    if (!skipInitialFetch) {

      refresh();

    }

  }, [endpoint]);

  return { value: valueRef.current, status, error, update, refresh };