Q:

React-Native Android - Release apk "has stopped" - Looking for "index.ios"

I've built a simple android react-native app that works fine on the device when I run react-native run-android.
I've followed the instructions here https://facebook.github.io/react-native/docs/signed-apk-android.html to generate a signed apk.
When I try this release apk with react-native run-android --variant=release I get "Unfortunately,  has stopped".
How do I find out what happens? Are there some logs somewhere?
The stuff I'm finding via google is about debugging. But I presumably can't as this is a release build.
Update
I find out how to view the logs - adb logcat *:S ReactNative:V ReactNativeJS:V
I get the following
10-14 11:24:42.129 29039 29060 E ReactNativeJS: Requiring unknown module "./index.ios".
10-14 11:24:42.177 29039 29060 E ReactNativeJS: Module AppRegistry is not a registered callable module (calling runApplication)
10-14 11:24:42.534 29039 29060 E ReactNativeJS: Module AppRegistry is not a registered callable module (calling unmountApplicationComponentAtRootTag)

Why is my android release apk looking for anything ios related? Have I configured something wrong?

A:

Answering my own question, I traced this to a component I found on GitHub. The index.android.js contained simply:
module.exports = require('./index.ios');
I ended up stripping my app back to the bare minimum content, deploying it to the phone and testing. Then adding a little bit more of the previously broken content before redeploying. A bit like git bisect but a lot more manual!
TL;DR - if I searched for index.ios in all .js files, including those in node_modules, I might have found it.

