passport.js

const passport = require('passport'),
      data = require('../../data/user-data.js')();

module.exports = function(app) {

    passport.serializeUser((user, done) => {
        if (user) {
           return done(null, user);
        }

       return done(null, false);
    });

    passport.deserializeUser((userId, done) => {
        data.findUserById(userId)
            .then(user => {
                if (user) {
                   return done(null, user);
                }

               return done(null, false);
            })
            .catch(err => {
                done(err, false);
            });

    });

    require('./local-strategy.js')(passport, data);

    app.use(passport.initialize());
    app.use(passport.session());
};