javascript - 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?

question from:https://stackoverflow.com/questions/29941208/express-error-typeerror-router-use-requires-middleware-function-but-got-a-o

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.

---

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.