callback and promises to return data from rethinkdb

retrieve.js

//db_query.js

//send group data
var retrieve_group = function(r, connection, gid, req, res, session, callback) {
    r.db(dbname).table(tbgroup).get(gid).run()
        .then(function(response) {
            //console.log('deleted');
            callback(response);
        })
        .catch(function(err) {
            console.log(err);
        });
}


//routes.js
send url = http://localhost:3000/gpage?gid=e61fec66-c67f-4753-b092-73ba41c9cef0

app.get('/gpage', function(req, res) {
    if (req.session['user_session']) {
        var email = req.session['user_email'];
        var gid = req.query.gid;

        query.retrieve_group(r, connection, gid, req, res, session, function(data) {

            //render the page data
            res.render('gpage', {
                title: 'gpage',
                user_email: req.session['user_email'],
                group: data
            });
        });
    } else {
        res.redirect('/');
    }
});