Does comment-reply.js need to be a standalone file?

For comment threading to work, there is call to comment-reply.js in header. My question is should we call this as it is, or we can copy content of that file in another bigger file where other javascript functions are placed?

I have only one javascript file in footer where I put all javascripts I use on page (because of performance reasons) and this is working without problem, but I want confirmation that this script will also work in that situation.

Thanks