Thanks for this well structured article!

You said that I/O requests run in a thread separated from the main thread! But not JavaScript either NodeJS supports multi threading. In fact if you want to do this you have to use a specific program like PM2 or Supervisor or Cluster from NodeJs but what makes NodeJs powerful is the event driven conception of JavaScript! So NodeJs/JavaScript can execute many functions almost at the same time and it is why it is powerful for I/O or file processing but all that are executed on the same thread! I think you can add it to your article.