React Native Android apps suddenly stopped working. __fbBatchedBridge(<unknown file>:1

This is all brand new. Two weeks ago all my React Native projects were working fine. I walked away for a week or two, and then yesterday when I went to test them, I was getting this error.

java.util.concurrent.ExecutionException: java.lang.RuntimeException: ReferenceError: Can't find variable: __fbBatchedBridge(<unknown file>:1)

There are a few below that,runJSBundle CatalystInstanceImpl.java:160 etc, but nothing that's telling me anything useful as to where the problem is.

This is happening on all my projects, both in the emulator and on my phone.

I've spent two days on this now, and have read all the questions I can find from the past couple months but none have an answer. My best guess is that some dependency got upgraded and that made things all wonky. But I haven't upgraded anything in the packages, so I don't know.

I'm open to any suggestions.

The package launcher looks like this:

[9:34:58 AM] <START> Building Dependency Graph
[9:34:58 AM] <START> Crawling File System
[Hot Module Replacement] Server listening on /hot

React packager ready.

[9:34:59 AM] <END>   Crawling File System (1208ms)
[9:34:59 AM] <START> Building in-memory fs for JavaScript
[9:35:00 AM] <END>   Building in-memory fs for JavaScript (357ms)
[9:35:00 AM] <START> Building in-memory fs for Assets
[9:35:00 AM] <END>   Building in-memory fs for Assets (286ms)
[9:35:00 AM] <START> Building Haste Map
[9:35:00 AM] <START> Building (deprecated) Asset Map
[9:35:01 AM] <END>   Building (deprecated) Asset Map (160ms)
[9:35:01 AM] <END>   Building Haste Map (535ms)
[9:35:01 AM] <END>   Building Dependency Graph (2392ms)