app.ios.js

// note:
// this code was taken almost as-is from the example project in react-native-controllers/index.ios.js
// sorry for mixing es5 and es6 syntax, but it should be very easy to upgrade the syntax here to es6

var Controllers = require('react-native-controllers');

// it's a good idea to separate all react-native-controllers specific code to a single separate file
// because we have a special React instance in this file
var React = Controllers.hijackReact();
var {
  ControllerRegistry,
  TabBarControllerIOS,
  NavigationControllerIOS,
  ViewControllerIOS,
  DrawerControllerIOS
} = React;

// this is our app controller layout, you can add tabs / side menu drawer
var MyApp = Controllers.createClass({
  render: function() {
    return (
      <NavigationControllerIOS
        title="Welcome"
        component="ExampleScreen"
        id="main"
        passProps={{}}
      />
    );
  },
});

ControllerRegistry.registerController('MyApp', () => MyApp);

function startApp() {
  // this line makes the app actually start and initialize
  ControllerRegistry.setRootController('MyApp');  
}

module.exports = startApp;