Like if I'm using print statements to test my code. Is it okay to leave stuff like that in there when "publishing" the app/program?

Edit: So I meant logging. Not "tests". Using console.log to see if the code is flowing properly. I'll study up on debugging. Also, based on what I managed to grasp from your very helpful comments, it is not okay to do, but the severity of how much of an issue it is depends on the context? Either that or it's completely avoidable in the first place if I just use "automated testing" or "loggers".