Invariant Violation: Module AppRegistry is not a registered callable module
Invariant Violation: Module AppRegistry is not a registered callable module (calling runApplication). A frequent cause of the error is that the application entry file path is incorrect. This can also happen when the JS bundle is corrupt or there is an early initialization error when loading React Native.
This issue appears if you have added some new library to your project, or you are switching branch or your bundle data got corrupted.
Start the server by resetting the cache.
npm start --reset-cache
then, start your android or ios app:
npm start android
npm start ios
If the above solution doesn’t work, you can try by deleting the node_modules folder:
rm -rf node_modules npm i or yarn i
Start the app again. One of these should work.