useGeoposition.js

import {
  useState,
  useEffect
} from "react";
import { createResource } from "react-cache";

let GeopositionResource = createResource(() =>
  new Promise((res, rej) =>
    navigator.geolocation.getCurrentPosition(
      position => res(position),
      error => rej(error)
    )
  )
);

let useGeoposition = () => {
  let initialPosition = GeopositionResource.read();
  let [position, setPosition] = useState(initialPosition);
  useEffect(() => {
    let watchId = navigator.geolocation.watchPosition(setPosition);
    return () => navigator.geolocation.clearWatch(watchId);
  }, []);

  return position;
};

export default useGeoposition;