app.set('port', port) 'TypeError: undefined is not a function'. Beginner, need ideas

Question

I\'m an amateur learning to build with node.js. I\'ve been following a tutorial to create my first node.js app. It worked perfectly until I entered \'npm start\'. The log is:

Answer 1

In my case I simply moved the normalizePort function before the function was called. This was in coffeescript but I've converted it to javascript here.

normalizePort = function(val) {
  var port;
  var port;
  port = parseInt(val, 10);
  if (isNaN(port)) {
    return val;
  }
  if (port >= 0) {
    return port;
  }
  return false;
};

port = normalizePort(process.env.PORT || '4000');

Answer 2

Intaned of calling export please use module.export end the end of your script.

exports = app;
module.exports = app;

Answer 3

At the bottom of your app.js:

app.set('port', process.env.PORT || 26398); //<--- replace with your port number

// Server
var server = http.createServer(app);
server.listen(app.get('port'), function(){
    console.log('Express server listening on port ' + app.get('port'));
});

module.exports = app;

Answer 4

You are not exporting anything in the app.js file. At the end of app.js file, include following line.

module.exports = app;

See whether your problem goes away.

And one more addition: you have var app = express(); twice in your app.js.

Answer 5

Just add "module.exports=app;" in the app.js file.

Answer 6

You don't have declared any function called set inside the app.js file. Create that function and export it like this:

exports.set = function(...) { ... };

If this app is the express app yo especify a port like this:

var express = require('express'),
    http = require('http');

var app = express();

http.createServer(app).listen(port);

instead of

app.set('port', port);
 /**
 * Create HTTP server.
 */

var server = http.createServer(app);

This is because the port is a property of the http server and not of the express app

You can use also

var express = require('express'),
    app = express();

app.listen(port);