Everytime you change the app you have to refresh web server. To overcome this problem Nodemon help auto update the web server in everychanges saved.
First you have to install nodemon a package with the code npm install nodemon in the terminal in VS Code.
Amrit@devkota MINGW64 /e/node/node_tutorial/node_basic (main)
$ npm install nodemon
The terminal should be directed to project directory.
When installation is completed and run the node app using nodemon index.js code in the terminal you don't need to restart the server on every changes made during development. nodemon thus also called development dependencies. It's of no use when the application come to production phase.