Actually, the time you need to deploy an app depends on how fast you are to copy & paste.

Prerequisites

Your code must be hosted in a git repository.

Steps to set up the environment the first time

1. Sign up (or log in) to <a href="http://heroku.com">heroku.com</a>
2. download <a href="https://devcenter.heroku.com/articles/heroku-cli">heroku's command for the console</a> (select the right version for your operating system).
3. be sure the command is installed: heroku -v (you should see some output)
4. launch heroku loginand log in with your email and password.
5. Upload ssh keys to heroku: heroku keys:add
6. ssh -v git@heroku.com: even if the command seems to fail, check that the long output contains the row

debug1: Authentication succeeded (publickey).

Generally it is one of the last 5-6 rows. If this log is present, everything is set up correctly.

Steps to set up the environment with the NodeJs app

• Set the host port of your application as an environment variable:

const port = process.env.PORT || 3000 ;  
... 
app.listen(port);

• set the npm start script, in package.json:

"scripts": {
   "start": "node server.js",
   ...
   }

• Check that the app runs correctly: npm start
• launch heroku create: will create a new remote for your repository named heroku
• git push heroku : will push your code to heroku
• heroku open: will open your webapp in the browser

For every modification you do to your code, just commit and git push heroku!