TypeError: Cannot read property 'DEFAULT_PORT' of undefined

TypeError: Cannot read property 'DEFAULT_PORT' of undefined

This issue is due to running with Default port instead of '27017'.

Change from 

module.exports = new Db(settings.db, new Server(settings.host, Connection.DEFAULT_PORT), {safe: true});

To

module.exports = new Db(settings.db, new Server(settings.host, '27017'), {safe: true});