A random JS alert is appearing only in production - how to debug in browser?

I'm looking for any way to try and debug where a javascript alert is coming from. The alert itself isn't helpful, it's just the number 2

It doesn't appear in the code at first glance (and globally searching is ~4k+ entries to look through), and is only showing up in a specific region in production. It does not show up on our development servers.

I've seen suggestions of adding a stack trace to every alert() call, but considering we cannot replicate it in our development environments and only in production, this isn't a viable option.

HELP! Is there a way to stack trace it directly in browser without pushing code to production? I'm almost wondering if it's somehow coming from the JQuery library etc.

Via Active questions tagged javascript - Stack Overflow https://ift.tt/H8QdEn7