TLDR; I was editing the wrong file, let's go to bed.

We have this huge system that receives data from an API endpoint, does a whole bunch of stuff, going through three other servers, and then via some calculation based on the data received from the UI, and data received from the endpoint, it finally sends the calculated fields to the UI via websocket.

Poor me sitting for over 4 hours debugging and changing values in the logic file trying to understand why one of the fields ends up being null.

Of course every change needs a reboot to all the 4 servers involved, and a hard refresh of the UI.

I even tried to search for the word null in that file, but to no avail.

After scattering hundreds of console logs, and pulling my hair out, I found out that I am editing the wrong file.

I guess it's time for some sleep.