Geocode custom function for Google Sheets

geocode.gs

/**
 * Geocode address using Google Maps
 *
 * @param address the address to geocode
 * @return the geocoded address (possibly approximate)
*/
function geocode(address) {
  var response = Maps.newGeocoder().geocode(address);
  var geom = response.results[0].geometry;
  return geom.location.lat + ", " + geom.location.lng;
}