Get next closest location

gistfile1.txt

function getNextClosestLocation(notification)
{
  var notif = new Notification(notification);
  //trigger when a due date marked complete
  var card = notif.completedDueDate();
  //build an array of distances between this card and all 
  //other cards on the board
  var distances = [];
  
  card.board().cards().each(function(loop)
  {
    distances.push({dist: getDistanceBetweenLocationsFromGoogleMapsApi(card.customFieldValue("Address"),
                                                                       loop.customFieldValue("Address")),
                    card: loop}                                        
    );
  });
  
  distances.sort(function(a,b)
  {
    return a.dist - b.dist;
  });
  
  if(distances.length)
    notif.replyToMember("Your next delivery is: "+distances[0].card.link());
}

function getDistanceBetweenLocationsFromGoogleMapsApi(address1,address2)
{
  //do this using the maps directions API:
  //https://stackoverflow.com/questions/4174642/google-apps-script-map-api-for-distance-calculation-between-two-points
  return distance;
}