Local database + Server database - React Native

Question

I ask myself lots of questions about the choice of databases for my future react-native application, because I would like a local database that stores the static data of the application. I would like also to store the data created by the user on a data server.

1. I thought using Realm for local storage
2. MongoDB for remote storage

Problem: I do not know how to synchronize remote data, because when the user is offline, I want the data to be stored locally and then when it goes offline, I want the data to be sent to the server

Can these two databases be used mutually, or is MongoDB able to store the data locally?

Answer 1

Consider using AsyncStoragefor local storage, andAppState to sync it with your db of choice (mongoDB is a good remote choice, but doesn't work locally). They're both native modules. AsyncStorage works like localStorage. When the app transitions from foreground to background is a good time to save data locally and remotely. It looks like this.

      _handleAppStateChange = (nextAppState) => {
if (this.state.appState.match(/inactive|background/) && nextAppState === 'active') {
  console.log('App has come to the foreground!')
  this.setState({appState: AppState.currentState});
} 
else if (this.state.appState.match(/active|background/) && nextAppState === 'inactive') {
  console.log('App has gone to background!')
   this.setState({appState: AppState.currentState});
}    


}

The documentation is excellent.

Answer 2

I am not sure how many data will you treat in local database, but MongoDB Stitch can be the one of solutions.

Stitch Mobile Sync.