<Router>
    <Scene key="root">
      <Scene key="login" component={Login} title="Login"/>
      <Scene key="register" component={Register} title="Register"/>
      <Scene key="home" component={Home}/>
    </Scene>
  </Router>

  <Tabs key="tabbar" 
    gestureEnabled={false} showLabel={false} tabs 
    tabBarStyle={styles.tabBarStyle} activeBackgroundColor="#ddd">
    <Scene key="tab1" title="Tab #1" icon={TabIcon}>
      <Scene
        key="tab2_1"
        component={Home}
        title="Tab #2_1"
      />
    </Scene>
    <Scene key="tab2" title="Tab #2" icon={TabIcon}>
      <Scene
        key="tab2_1"
        component={Home}
        title="Tab #2_1"
      />
    </Scene>
  </Tabs>

try {
  /* set data */
  await AsyncStorage.setItem('@MySuperStore:key', 'Save it.');

  /* get data */
  const value = await AsyncStorage.getItem('@MySuperStore:key');

} catch (error) {
  // Error saving data
}

import { Platform, StyleSheet } from 'react-native';

const styles = StyleSheet.create({
  height: (Platform.OS === 'ios') ? 200 : 100,
});

import { Platform, StyleSheet } from 'react-native';

const styles = StyleSheet.create({
  container: {
    flex: 1,
    ...Platform.select({
      ios: {
        backgroundColor: 'red',
      },
      android: {
        backgroundColor: 'blue',
      },
    }),
  },
});

const BigButton = require('./BigButton');

<Animated.View              // Special animatable View
    style={{
      ...this.props.style,
      opacity: fadeAnim,    // Bind opacity to animated value
    }}
>
  {this.props.children}
</Animated.View>

state = {
  // Initial value for opacity: 0
  fadeAnim: new Animated.Value(0),  
}

Animated.timing(        // Animate over time
  this.state.fadeAnim,  // The animated value to drive
  {
    toValue: 1,         // Animate to opacity: 1 (opaque)
    duration: 10000,    // Make it take a while
  }
).start();   

$ react-native bundle --platform ios 
--dev false 
--entry-file index.ios.js 
--bundle-output iOS/main.jsbundle 

$ node node_modules/react-native/local-cli/cli.js bundle 
--platform android 
--dev false 
--entry-file index.android.js 
--bundle-output android/app/src/main/assets/index.android.bundle 
--assets-dest android/app/src/main/res