/**
* Get the number of messages unread
*/
function getNumberUnreadMail(){
// Get Active user
var email= Session.getActiveUser().getEmail();
// Get "Unread" Labels Informations
var response = Gmail.Users.Labels.get(email,'UNREAD');
// TODO : manage value of response & errors
if(response){
var unreadNumber = response.messagesUnread;
// return Total Number of Messages Unread
return unreadNumber;
} else {
Logger.log('Erreur');
}
}