restify-router with group - Javascript - Nested middleware usage

server.js

/**
 *
 * Will create like this:
 * 
 * /v1 [midFirst]
 * /v1/auth/register [midFirst, midSecond, midThird]
 * 
 */
var Router = require('restify-router').Router;
var restify = require('restify');

var routerInstance = new  Router();
var server = restify.createServer();

function midFirst(req, res, next) { /**/ }
function midSecond(req, res, next) { /**/ }
function midThird(req, res, next) { /**/ }

routerInstance.group('/v1', midFirst, function (router) {
  router.get('/', function (req, res, next) {
    res.send({message: 'home V1'});
    return next();
  });

  router.group('/auth', midSecond, function (router) {
    router.post('/register', midThird, function (req, res, next) {
      res.send({message: 'success (v1)'});
      return next();
    });
  });
});

// add all routes registered in the router to this server instance
routerInstance.applyRoutes(server);

server.listen(8081, function() {
  console.log('%s listening at %s', server.name, server.url);
});