Use SharedPreference (Android) and UserDefaults (iOS) with React Native over a unified interface. All data are stored as String, in case more complex data structure is needed, serialize it (e.g. JSON)

$ npm install react-native-default-preference --save

$ react-native link react-native-default-preference

1. In XCode, in the project navigator, right click Libraries ➜ Add Files to [your project's name]
2. Go to node_modules ➜ react-native-default-preference and add RNDefaultPreference.xcodeproj
3. In XCode, in the project navigator, select your project. Add libRNDefaultPreference.a to your project's Build Phases ➜ Link Binary With Libraries
4. Run your project (Cmd+R)<

1. Open up android/app/src/main/java/[...]/MainActivity.java

• Add import com.reactlibrary.RNDefaultPreferencePackage; to the imports at the top of the file
• Add new RNDefaultPreferencePackage() to the list returned by the getPackages() method

2. Append the following lines to android/settings.gradle:

   include ':react-native-default-preference' project(':react-native-default-preference').projectDir = new File(rootProject.projectDir,	'../node_modules/react-native-default-preference/android') 

3. Insert the following lines inside the dependencies block in android/app/build.gradle:

    compile project(':react-native-default-preference') 

import DefaultPreference from 'react-native-default-preference'; DefaultPreference.get('my key').then(function(value) {console.log(value)}); DefaultPreference.set('my key', 'my value').then(function() {console.log('done')});

function get(key:String):Promise<String>; function set(key:String, value:String):Promise<Void>; function clear(key:String):Promise<Void>; function getMultiple(keys:Array<String>):Promise<Object>; function setMultiple(data:Object):Promise<Void>; function clearMultiple(keys:Array<String>):Promise<Void>; function getAll():Promise<Object>; function clearAll():Promise<Void>;