Check following React Native Android/iOS applications which implement local storage and database
Local storage is often used to store user specific data, application state or to provide offline content
Following are some applications implementing local storage and database
An application might require local storage to store information about user's activity and/or profile
Platform: Android & iOS
Check React Native Json Storage application code
SQFlite is a plugin used in React Native to perform database operations for both Andoid and IOS apps
Platform: Android & iOS
Check React Native Local Database Application code