how do I change some data on UI without refreshing the screen in a web app using node js? I need to change only a few things on the screen. And one more doubt is how the data update on screen whenever the data on the database changes.
You do not have any code here, so I can't give you the exact answer for your situation. And You have not told me how you want it to not 'refresh' e.g a button click or something like that.
In your case my best tip would be to check out Socket.io, socket.io is a framework in Nodejs that can help you interact with WebSockets. A WebSocket is a direct connection between the client and server and does not require a trigger on the client. Instead of working around it by fetching data every couple of seconds in the app. Jeff from fireship has done a better explanation of this topic you can watch his video here: https://www.youtube.com/watch?v=1BfCnjr_Vjg
Official socket.io documentation: https://socket.io/docs/v4/
Hope this helps!