Replace string with random number/string using regex

I have a angular project, we are using a plugin to show loading indicator.

The function goes like this this.loading('Loading message')

Here Loading message is written everywhere. I need to find that exact source.

What I want to do is, replace the Loading message with <random string/number> so that I can get exact source.

I am using notepad++, visual studio code. Can I do that using regex or any other way?

P.S. I have tried every other way, it is not possible to find the root cause any other way!