If you plan to publish your app, there's one thing you're going to need sooner or later: internationalization (I18n) and localization (L10n). That's what Alexander Zaytsev has brought to React Native by integrating i18n-js.

react-native-i18n on GitHub

Integrates I18n.js with React Native. Uses the device's locale as default.

var I18n = require('react-native-i18n');

var Demo = React.createClass({  
  render: function() {
    return (
      <Text>{I18n.t('greeting')}</Text>
    )
  }
});

I18n.translations = {  
  en: {
    greeting: 'Hi!'
  },
  fr: {
    greeting: 'Bonjour!'
  }
}