Simple but more complex example (backend and frontend) for node.js?

I've only been familiar with node.js and actually Javascript for five days.
I'm trying to find an example or tutorial that contains a simple but comprehensive example combining backend and frontend.
Something like.
Virtual light bulb and switch, the light bulb has an hour meter and energy consumption. I can monitor the light bulb via the web, change its state with a switch.
Or just monitor whether it is on and how long it has been on, using AJAX for this.

Of course, it doesn't have to be this, it just seemed like the simplest description of what I'm looking for.

Can you tell me where I can find something like this?

Thank you in advance.