if (Boolean(window.navigator.geolocation)) {
  // It supports
  ...
}

window.navigator.geolocation.getCurrentPosition(
    positionCallback,
    errorCallback
);

function positionCallback(position) {
  // Assigning coords object for easier access.
  const coords = position.coords;

  // Position of the longitude .
  const longitude = coords.longitude;

  // Position of the latitude.
  const latitude = coords.latitude;

  // Accuracy of latitude & longitude in meters.
  const accuracy = coords.accuracy;

  // Altitude in meters, relative to sea level.
  const altitude = coords.altitude;

  // Accuracy of the altitude in meters. Value can be null.
  const altitudeAccuracy = coords.altitudeAccuracy;

  // Direction towards which the device is facing. This value specified
  // in degrees clockwise from North. Value can be null.
  const heading = coords.heading;

  // The velocity of the device in m/s. Value can be null.
  const speed = coords.speed;

  // The time at which the location was retrieved.
  const time = position.timestamp;
}

function errorCallback(err) {
  let msg;
  switch (err.code) {
    case err.PERMISSION_DENIED:
        msg = "User denied the request for Geolocation.";
        break;
    case err.POSITION_UNAVAILABLE:
        msg = "Location information is unavailable.";
        break;
    case err.TIMEOUT:
        msg = "The request to get user location timed out.";
        break;
    case err.UNKNOWN_ERROR:
        msg = "An unknown error occurred.";
        break;
  }
}

const id = window.navigator.geolocation.watchPosition(
   positionCallback,
   errorCallback
);

window.navigator.geolocation.clearWatch(id);