Add session support to express after setup

I am just starting to figure out nodejs and I forgot to put in the flag for session support

$ express -s somefolder

Can I run the above command without overwriting anything I already added or changed or do I have to do something else?

it is not as clear as adding a new dependancy (stylus) to package.json and rerun $ npm install

Just add the session middleware to your Express app.js file.

app.use(express.cookieParser());
app.use(express.session({secret: '1234567890QWERTY'}));

Make sure it comes after the express.cookieParser() call. Also, update the secret value to a random string for security.