How to debug react-native iOS app crashing on startup after a week or so

Question

I started messing around with react-native. I've built a small application and it seems to work fine ( package.json ). I can work on it in Debug or Release mode, using the simulator or my iPhone 6S device, and all is well.

This app is just for me so I don't pay for the Apple Developer thing, and I just run the app in Release mode on my device, and it...seems to be fine? I can quit xcode and go places and the app works fine.

After a week or so, it's hard to tell, the app stops loading. It'll display the splash screen for a split second and then it's gone back to the home screen.

I setup Rollbar, but it doesn't catch anything. I look in the Privacy -> Analytics area and don't see anything there either.

I'm not really looking for an answer to my exact problem since various SO questions and other places suggest it's probably something weird and specific. My main problem is I don't know even where to look/how to debug this kind of thing. If I build the app and run it on device again, it'll run fine. I need to try to debug without loading new code, and have no idea how that works on iOS. I've tried poking around at the Debug -> Attach to Process by Name, but the app never gets far enough to do anything with that.

Alternatively, I throw react-native in the garbage and use something that works...

Answer 1

App provisioning with a free developer license (?) is 7 days. See: Why does my free XCode Provisioning Profile only last 7 days?

You can likely verify this by looking at error messages in the console window. Connect your device, and in Xcode go to Window/Devices and Simulators/Open Console, then launch your app.