referencing constants and variables across separate class files - reactjs

Question

My App.js file was getting very large, so I decided to move out all my classes to their own separate file, and this is what remains in my App.js
import React from 'react';
import {
AppRegistry,
Text,
View,
Button,
Image
} from 'react-native';
import { StackNavigator } from 'react-navigation';
import { TabNavigator } from 'react-navigation';
//screen imports
import RecentChatScreen from './RecentChatScreen';
import AllContactsScreen from './AllContactsScreen';
import ChatScreen from './ChatScreen';
import HomeScreen from './HomeScreen';
import InfoScreen from './InfoScreen';
const MainScreenNavigator = TabNavigator({
Home: { screen: HomeScreen },
Recent: { screen: RecentChatsScreen },
All: { screen: AllContactsScreen },
});
const NavTest = StackNavigator({
Home: { screen: MainScreenNavigator },
Chat: { screen: ChatScreen },
Info: { screen: InfoScreen }
});
I think that looks fine.
However in some of the class files, I need to reference those other screens in button events, like this:
onPress={ () => navigate('Home')}
This worked fine before when everything was in App.js, but how would I reference these screens(Home, Chat, Info, Recent, All) now in the their separate files when the definitions are in App.js?
Thanks!

Answer 1

You can export them in App.js:
// App.js
// ...
export {
MainScreenNavigator,
NavTest,
}
And then import them from it:
import {MainScreenNavigator, NavTest} from './path/to/App.js';

Answer 2

If your intent is just to navigate to the different screens, and not use any properties defined within a particular screens class, then you would not need to import anything. When you define the StackNavigator and lets say you are passing in that value into the AppRegistry as the entry point of the application. In your case, it could be something like this:
AppRegistry.registerComponent('NavTest', () => NavTest)
Now within any of the screens, the navigatation object is passed in as a prop. You can then use that to navigate to any of the defined screens. The initial setup of the StackNavigator is essentially a mapping from a routeName to a react component (a class). So when you want to navigate to a particular class, all you need is the name of the route not the class or component it represents, the navigator already has all that. This name would be the key passed into the StackNavigator for a particular screen. In your example, the routeNames are Home, Chat and Info. So just doing something like this would work:
const { navigate } = this.props.navigation;
return (
<View>
<Text>Navigate Test</Text>
<Button onPress={() => navigate('Chat')} title="Go to chat"/>
</View>
);