Weird Error Trying to Start Expo On Mobile

After being able to successfully deploy my app to my android device for the past several days, and multiple times today already, I received the following error:

undefined is not an object (evaluating ‘ua.indexOf’)

The first message says
platform=android&dev=true&hot=true&minify=false: 94274:18

I’ve tried rolling my code back to where it was before the error started occurring, and both LAN and localhost publishing in XDE, but neither of those worked.

I am using an Motorola Nexus 6 physically connected to my development machine via a usb cable.

Does anybody know what could be causing this?

I was able to do enough stuff that the problem went away. 1st I followed all the steps from here: Expo SDK v16.0.0 is now available | by Brent Vatne | Exposition, then I made sure my XDE launched my project in dev mode. Finally, I made sure the app on my device was starting in debug mode and that I had a Chrome inspection window open.