db.model("users").findOne({username: username, password: password}, {type:1},
    function(err, data) {
        if(err) {
            return "Error";
        } else if() {
            return "No records";
        } else {
            return data.type;
        }
    }
);

var Database = function {
  var myText = null;

  return {

    getUser: function(username, password, callback) {
      db.model("users").findOne({username: username, password: password}, {type:1},
           function(err, data) {
             if (err) {
               myText = "Error";
             }
             else if (data.length == 0) {
               myText = "No records";
             }
             else {
               myText = data.type
             }

             $('.log').html(myText);
             callback(myText);
      });
    };
  };
}();

Database.getUser(username, password, function(theText) { alert(theText); });