error in socket.io code execution - node.js

Question

From the Digital Ocean Community at this url, https://www.digitalocean.com/community/tutorials/how-to-install-express-a-node-js-framework-and-set-up-socket-io-on-a-vps, I encounter an eroor when trying to execute Part 4: The Server Code. The article states "Go and open up the app.js file in the Express application folder. Inside you'll a bunch of auto-generated code, delete all of it and use the following example instead:"
Here is the code:
/**
* Module dependencies.
*/
var express = require('express')
, routes = require('./routes')
, http = require('http');
var app = express();
var server = app.listen(3000);
var io = require('socket.io').listen(server); // this tells socket.io to use `our express server`
app.configure(function(){
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.static(__dirname + '/public'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
});
app.configure('development', function(){
app.use(express.errorHandler());
});
app.get('/', routes.index);
console.log("Express server listening on port 3000");
When I make these changes to app.js and then try to execute the app I get the following error:
/root/socketio-test/app.js:9
var app = express();
^
TypeError: object is not a function
at Object.<anonymous> (/root/socketio-test/app.js:9:11)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:902:3
I have no idea how to correct this error.
System info: Ubuntu LEMP on 14.04
node.js installed, express installed, socket.io installed.

Answer 1

I believe you have some how installed the wrong version of express..
Do a express --version before express 3.x express was not a function.
I tried to install npm install express -g on a new droplet and I cannot get express to be an executable.
As far as I understand the express skeleton generator was moved into a separate package which can be installed using npm install express-generator -g
Which will give you the command line executable express, after you install express-generator you should be good to go.
http://expressjs.com/en/starter/generator.html
I think DO needs to update their tutorial.