MEAN API , getting undefined is not a function - node.js

Question

I am trying to implement a simple API but get undefined is not a function when I navigate to api/users. Spent hours trying to figure this out, any suggestions would be greatly appreciated.
Stack trace
TypeError: undefined is not a function
at module.exports (//config/routes.js:10:9)
at Layer.handle [as handle_request] (/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (/node_modules/express/lib/router/index.js:312:13)
at /U/node_modules/express/lib/router/index.js:280:7
at Function.process_params (//node_modules/express/lib/router/index.js:330:12)
at next (//node_modules/express/lib/router/index.js:271:10)
at logger (//node_modules/morgan/index.js:144:5)
at Layer.handle [as handle_request] (/U/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (//node_modules/express/lib/router/index.js:312:13)
at //node_modules/express/lib/router/index.js:280:7
at Function.process_params (//node_modules/express/lib/router/index.js:330:12)
at next (//node_modules/express/lib/router/index.js:271:10)
at SessionStrategy.strategy.pass (//node_modules/passport/lib/middleware/authenticate.js:318:9)
at SessionStrategy.authenticate (//node_modules/passport/lib/strategies/session.js:67:10)
at attempt (//node_modules/passport/lib/middleware/authenticate.js:341:16)
at authenticate (//node_modules/passport/lib/middleware/authenticate.js:342:7)
I have the following setup.
app.js
'use strict';
var express = require('express');
var env = 'development';
var app = express();
var config = require('./config/config')[env];
require('./config/mongoose')(config);
require('./config/express')(app, config);
require('./config/passport')();
require('./config/routes')(app);
app.listen(config.port, function() {
console.log('Express server listening on port ' + config.port);
console.log('env = ' + app.get('env') +
'\n__dirname = ' + __dirname +
'\nprocess.cwd = ' + process.cwd());
}
express.js
/* jshint -W117 */
var express = require('express'),
logger = require('morgan'),
bodyParser = require('body-parser'),
favicon = require('serve-favicon'),
cookieParser = require('cookie-parser'),
env = 'development',
session = require('express-session'),
passport = require('passport'),
four0four = require('../utils/404')();
module.exports = function(app, config) {
app.use(favicon(config.rootPath + '/favicon.ico'));
app.use(cookieParser());
app.use(bodyParser.urlencoded({extended: true}));
app.use(bodyParser.json());
app.use(session({resave: false, saveUninitialized:false,
secret: 'all is well that ends well'}));
app.use(passport.initialize());
app.use(passport.session());
app.use(logger('dev'));
app.use('/api', require('./routes'));
console.log('About to crank up node');
console.log('PORT=' + config.port);
console.log('NODE_ENV=' + env);
switch (env){
case 'production':
console.log('** BUILD **');
app.use(express.static('./build/'));
// Any invalid calls for templateUrls are under app/* and should return 404
app.use('/app/*', function(req, res, next) {
four0four.send404(req, res);
});
// Any deep link calls should return index.html
app.use('/*', express.static('./build/index.html'));
break;
default:
console.log('** DEV **');
app.use(express.static('./src/client/'));
app.use(express.static('./'));
app.use(express.static('./tmp'));
// Any invalid calls for templateUrls are under app/* and should return 404
app.use('/app/*', function(req, res, next) {
four0four.send404(req, res);
});
// Any deep link calls should return index.html
app.use('/*', express.static('./src/client/index.html'));
break;
}
}
routes.js
var four0four = require('../utils/404')(),
auth = require('../config/auth'),
users = require('../controllers/users'),
mongoose = require('mongoose'),
User = mongoose.model('User');
module.exports = function(app) {
app.get('/users', auth.requiresRole('admin'), users.getUsers);
app.post('/users', users.createUser);
app.put('/users', users.updateUser);
app.post('/login', auth.authenticate);
app.post('/logout', function(req, res) {
req.logout();
res.end();
});
app.all('/*', four0four.notFoundMiddleware);
}
auth.js
var passport = require('passport');
exports.authenticate = function(req, res, next) {
req.body.username = req.body.username.toLowerCase();
var auth = passport.authenticate('local', function(err, user) {
if (err) {return next(err);}
if (!user) {res.send({success:false});}
req.login(user, function(err) {
if (err) {return next(err);}
res.send({success:true, user:user});
});
});
auth(req, res, next);
};
exports.requiresApiLogin = function(req, res, next) {
if (!req.isAuthenticated()) {
res.status(403);
} else {
next();
}
};
exports.requiresRole = function(role) {
return function(req, res, next) {
if (!req.isAuthenticated() || req.user.roles.indexOf(role) === -1) {
res.status(403);
res.end();
} else {
next();
}
};
}

Answer 1

I solution to this problem was a complete refactor of my routes.js file. I also removed this line from the app.js
require('./config/routes')(app);
Here is how the routes.js file looks after the refactor.
var four0four = require('../utils/404')(),
auth = require('../config/auth'),
users = require('../controllers/users'),
mongoose = require('mongoose'),
User = mongoose.model('User'),
router = require('express').Router();
router.get('/users', auth.requiresRole('admin'), users.getUsers);
router.post('/users', users.createUser);
router.put('/users', users.updateUser);
router.post('/login', auth.authenticate);
router.post('/logout', logoutUser);
router.all('/*', four0four.notFoundMiddleware);
module.exports = router;
//////////////
function logoutUser (req, res){
req.logout();
res.end();
}