Express error - TypeError: Router.use() requires middleware function but got a Object

Question

I am getting this error when I run npm start to run my express app.

TypeError: Router.use() requires middleware function but got a Object 

my app.js code

var express = require('express'); var path = require('path'); var favicon = require('serve-favicon'); var logger = require('morgan'); var cookieParser = require('cookie-parser'); var bodyParser = require('body-parser');  var routes = require('./routes/index'); var users = require('./routes/users');  var app = express();  // view engine setup app.set('views', path.join(__dirname, 'views')); app.set('view engine', 'ejs');  // uncomment after placing your favicon in /public //app.use(favicon(__dirname + '/public/favicon.ico')); app.use(logger('dev')); app.use(bodyParser.json()); app.use(bodyParser.urlencoded({ extended: true })); app.use(cookieParser()); app.use(express.static(path.join(__dirname, 'public')));  app.use('/', routes); app.use('/users', users);    /// catch 404 and forwarding to error handler app.use(function(req, res, next) {     var err = new Error('Not Found');     err.status = 404;     next(err); });  /// error handlers  // development error handler // will print stacktrace if (app.get('env') === 'development') {     app.use(function(err, req, res, next) {         res.status(err.status || 500);         res.render('error', {             message: err.message,             error: err         });     }); }  // production error handler // no stacktraces leaked to user app.use(function(err, req, res, next) {     res.status(err.status || 500);     res.render('error', {         message: err.message,         error: {}     }); });  module.exports = app; 

my index.js code

var express = require('express'); var router = express.Router();  /* GET home page. */ router.get('/', function(req, res) {     res.render('index', { title: 'Express' }); });  /* GET Hello World page. */ router.get('/helloworld', function(req, res) {     res.render('helloworld', { title: 'Hello, World!' }) });  module.exports = router; 

I am quirte new to using Node and express. I cant see where I have gone wrong. Can anybody see what my problem is?

Answer 1

I found the answer in the comments from Kop4lyf:

check your users.js. It should also be exporting the router like index.js, if you can try that.

However, this question was my top search result when I ran into this issue, so I am promoting to an answer.

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The error is caused because one of your route modules is not being exported - meaning Express does not have access to it when it tries to identify all of your routes.

You can fix this by adding module.exports = router; to the end of each of your route files.

Example:

var express = require('express'); var router = express.Router();  router.get('/', function(req, res, next) {      //Do whatever... });  module.exports = router; 

More information about module.exports can be found on this question or the offcial Node.js documentation.

Answer 2

I have fixed this by adding which i am using somewhere. So please check your all exports.

module.exports = router;