Hapi.js error handling

index.js

const Hapi = require('hapi');
const server = new Hapi.Server();
server.connection({ port: 3000 });

// routes
server.route(require('routes'));

// error handlers
server.ext('onPreResponse', (request, reply) => {
  if (request.response.isBoom) {
    // Inspect the response here, perhaps see if it's a 404?
    return reply.redirect('/');
  }
  
  return reply.continue();
});

// start server
server.start(err => {
  if (err) throw err;
  console.log(`Server running at: ${server.info.uri}`);
});

routes.js

module.exports = [
  {
    method: 'GET',
    path: '/user/{id}',
    handler: (request, reply) => {
      User
        .findById(request.params.id)
        .then(user => {
          user
            .getSubjects()
            .then(subjects => {
              reply(Object.assign({}, user.get(), {
                subjects: subjects
              }))
            });
        })
        .catch(err => {
          reply(Boom.notFound('User not exsit'));
        })
    }
  }
];