Do something if nothing found with .find() mongoose

When there are no matches find() returns [], while findOne() returns null. So either use:

Model.find( {...}, function (err, results) {
    if (err) { ... }
    if (!results.length) {
        // do stuff here
    }
}

or:

Model.findOne( {...}, function (err, result) {
    if (err) { ... }
    if (!result) {
        // do stuff here
    }
}

I had to use:

 if(!users.length) { //etc }

to get it to work.

UserModel.find({ nick: act.params }, function (err, users) {
  if (err) { console.log(err) };
  if (!users.length) { //do stuff here };
  else {
    users.forEach(function (user) {
      console.log(user.nick);
    });
  }
});

is what I found to work.