Question: I'm working on a codebase with multiple blocks of code setting some behavior on document.ready() (jQuery). Is there a way to enforce that one specific block is called before any of the others? 

Background:
I need to detect JS errors in an automated testing environment, so I need the code that starts logging JS errors to execute before any other JS code executes.

Answer: 
I was trying to do something similar, I was loading a bunch of polyfills that had .ready() functions, but I also had my own .ready()s on page that I needed executed first, though the polyfills were loaded in the header.

I found a nice way around it by having a .ready() very early on (right after jQuery loads) that executes functions from an array. Because it's very early in the source code it's .ready() is executed first. Further down the page I can add functions to the array and, so they all execute before any other .ready()s.

I've wrapped it up in a .beforeReady() function and put it on GitHub as jQuery-Before-Ready for anyone that is interested. 
<https://github.com/aim12340/jQuery-Before-Ready>
You can execute the logging start code in DOMReady and other initialization in load. Or you could make your own initialization manager which calls your logging start code first and then all other initialization callbacks (provided that those are registered with your manager and not jQuery, unless you want to hack jQuery and extract them from there, which I don't advise).