Express.js MVC app routing render function undefined

Question

I am working through Amos Q. Haviv's MEAN Web development textbook. It was going fine, but I ran into an error working with Express.js that I can't seem to find an answer for online. There are no comments about the book or anything that outline this error, and I can't find any helpful answers. I'm working on a simple index page:

Version of Express used in the book is: 4.8.8 My latest version is: 4.12.4

Controller:

var express = require('express');

var hasName = function(req, res, next) {
    if (req.params.name) {
            next();
    } else {
            res.send('What is your name?');
    }
};

var sayHello = function(req, res, next) {
    res.send('Hello ' + req.params.name);
};

var app = express();
app.get('/', hasName, sayHello);

app.listen(3000);

console.log('Server running at http://localhost:3000/');

Route:

module.exports = function(app) {
    var index = require ('../controllers/index.server.controller');
    app.get('/', index.render);
};

Express config file:

var express = require('express');

module.exports = function() {
    var app = express();
    require('../app/routes/index.server.routes')(app);
    return app;
};

Server.js:

var express = require('./config/express');

var app = express();

app.listen(3000);

module.exports = app;

console.log('Server running at http://localhost:3000/');

And finally, the error message that comes up when I start the server:

Error: Route.get() requires callback functions but got a [object Undefined]
    at Route.<anonymous> (...\node_modules\express
\lib\router\route.js:170:15)
    at Array.forEach (native)
    at Route.(anonymous function) [as get] (...\no
de_modules\express\lib\router\route.js:166:15)
    at EventEmitter.app.(anonymous function) (...\
node_modules\express\lib\application.js:465:19)
    at module.exports (...\app\routes\index.server
.routes.js:3:9)
    at module.exports (...\config\express.js:5:49)
    at Object.<anonymous> (...\server.js:3:11)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)

The point of failure seems to be that when

app.get('/', index.render);

Is called, it errors out because index is undefined/an empty object. I have not been able to determine why this is happening.

If I export the app end of the controller .js file with module.exports, the server will start up, but will later error out with something else. I have tried everything I can think of to fix this, including copy-pasting the examples from the book exactly. I really want to be able to follow the book until I can grasp this development stack. Any help is appreciated.

Answer 1

Obviously this module :

require ('../controllers/index.server.controller'),

is not exporting an object which defines any render property / function.

Ensure this module exports a render function with this signature:

...
module.exports = { render: function(req, res, next) {...}, ... }
...