React-Native: Invariant Violation: Module AppRegistry is not a registered callable module (calling runApplication)

Question

My app builds in Xcode, the splash screen pops up on the ios simulator, then nothing happens. I have tried restarting the metro bundler, wiping the metro bundler's cache, reinstalling all pods, reinstalling all node modules, and rebuilding the app. I receive the following feedback from the Xcode terminal:

2020-04-24 17:02:50.186 [error][tid:com.facebook.react.JavaScript] TypeError: undefined is not an object (evaluating '_argonTheme.argonTheme.COLORS')
2020-04-24 17:02:50.190 [fatal][tid:com.facebook.react.ExceptionsManagerQueue] Unhandled JS Exception: TypeError: undefined is not an object (evaluating '_argonTheme.argonTheme.COLORS')
2020-04-24 17:02:50.198 [error][tid:com.facebook.react.JavaScript] Invariant Violation: Module AppRegistry is not a registered callable module (calling runApplication)
2020-04-24 17:02:50.376 [fatal][tid:com.facebook.react.ExceptionsManagerQueue] Unhandled JS Exception: Invariant Violation: Module AppRegistry is not a registered callable module (calling runApplication)

Answer 1

For me, this was caused by a faulty import statement. The Xcode terminal gave very little detail, so I had to comment out each import statement from every screen to find the culprit.