How can i know if a line has been written in STDOUT before removing stuff?

Basically i wanna clear the current line, with a progress tracker, with

process.stdout.clearLine(0);

but i wanna check before if it still is the line i wrote there, or a warning/error message from some of the submodules, because these should of course not be removed

I can't find a way to read from STDOUT, which is understandable, but there also seems to be no way of reading stuff from something like a write event or by intercepting the stream, this all only seems possible for the STDIN stream...