React Native App crashes on Launch Screen on device - ios

Question

I'm starting with React Native, everything works fine in the iOS simulator. I decide to try it on a device.
The app launches, I can play with it, I close/reopen it around 4 or 5 times, and then somewhat randomly the app crashes on Launch Screen (the one with "Powered By React Native"). It just shows the screen, and the app crashes to the iPhone home screen.
Any idea how I can further debug that?
Edit: I added Bugsnag in my AppDelegate.m, but bugsnag doesn't detect anything when the app crashes.
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSURL *jsCodeLocation;
[BugsnagReactNative start];
// Rest of code
}

Answer 1

I came across this issue today. Read a few SO posts and saw one guy mentioned if your app launches and hangs on the splash screen and then crashes with no error it probably has something to one of your npm dependencies.
After digging deeper i saw the react packager was throwing the error
This error is caused by a #providesModule declaration with the same name across two different files.
To fix
check / clean up dependencies(check for same name declerations)
rm -rf node_modules
rm -rf $TMPDIR/react-*
npm i

Answer 2

This can caused by many issues it seems. Recently this happened to me and I had to search a bit to find out the exact reason.
I'll save you guys the trouble by sharing few places I read
- https://github.com/facebook/react-native/issues/14500#issuecomment-348063910
- https://github.com/facebook/react-native/issues/17276#issuecomment-357538208
In my case it was a library issue which I have not linked properly.
-https://github.com/ivpusic/react-native-image-crop-picker/issues/204
So yeah! my point is, it's something we have done or not done. Bit more research would help!!!

Answer 3

I had a similar issue. My application crashed on emulator device every time I ran the application without throwing any error in the console.
Here are a bunch of solutions that might work:
Solution 1 Remove node_modules
rm -rf /node_modules
npm install
Solution 2 Remove /android/app/build directory (This one worked for me)
rm -rf /android/app/build
After this, uninstall the application from emulator device and then run your application again

Answer 4

I was also facing the same issue on real device and it was working fine on simulator. So, i have fixed my issue by given solution
Solution: i have uninstall the application from simulator and then installed it again. This time it showed me the actual error on simulator that i had made mistake.

Answer 5

I finally solve this error by running the app in release mode from xcode
goto Product->Scheme and then click edit Scheme
Select run from left side menu
change Debug to Release
untick Debug executable
now clean the project and run your app in release mode
Some time you have to delete pods and install again after doing above
look for your error in xcode console in my case VS code has imported a Library I just have to remove that import

Answer 6

I had this problem also, what triggered it for me though was updating react and react-native.
I did a build after updating and then I experienced the same issue. I downgraded back to the previous versions of react and react-native, but that didn't work for me.
I tried removing node modules, and reinstalling, that didn't help. Then I noticed that when I was building: react-native run-ios,
the files in ios/build were not updating
I rm -rf ios/build/ and then I react-native run-ios and the ios/build folder populated. My app ran fine after that.

Answer 7

For me lottie package was creating problem. After removing the package able to launch the package.
Make sure by checking the last package/packages installed

Answer 8

In my case it was the Firebase GoogleService-info.plist file which was missing that is supposed to be present in your project.xcodewrkspc when opened using XCode. Adding that resolved the issue.