React hook for geolocation

useGeolocation.ts

import React from "react";

export function useGeolocation({
  isEnabled,
  positionOptions: { enableHighAccuracy, maximumAge, timeout },
  startTransition,
}: {
  isEnabled: boolean;
  positionOptions: PositionOptions;
  startTransition?(update: () => void): void;
}) {
  const [state, setState] = React.useState<
    | { position: GeolocationPosition; error: undefined }
    | { position: undefined; error: GeolocationPositionError }
    | { position: undefined; error: undefined }
  >({ position: undefined, error: undefined });
  React.useEffect(() => {
    if (isEnabled) {
      const watcher = navigator.geolocation.watchPosition(
        (position) => {
          const update = () => setState({ position, error: undefined });
          if (startTransition) startTransition(update);
          else update();
        },
        (error) => {
          const update = () => setState({ position: undefined, error });
          if (startTransition) startTransition(update);
          else update();
        },
        { enableHighAccuracy, maximumAge, timeout }
      );
      return () => {
        navigator.geolocation?.clearWatch(watcher);
      };
    }
  }, [enableHighAccuracy, isEnabled, maximumAge, startTransition, timeout]);
  if (isEnabled) return state;
  else return { position: undefined, error: undefined };
}

export function getGeolocation(positionOptions: PositionOptions) {
  return new Promise<GeolocationPosition>((resolve, reject) => {
    navigator.geolocation.getCurrentPosition(resolve, reject, positionOptions);
  });
}