React Native and ReactNavigation: Disable Android's hardware back button for specific screen

getStateForAction.js

const defaultGetStateForAction = AppNavigator.router.getStateForAction;

AppNavigator.router.getStateForAction = (action, state) => {
    const screen = state ? state.routes[state.index] : null;
    const tab = screen && screen.routes ? screen.routes[screen.index] : null;
    const tabScreen = tab && tab.routes ? tab.routes[tab.index] : null;

    if (
        action.type === NavigationActions.BACK &&
        tab && tab.routeName === 'EventsTab' &&
        tabScreen && tabScreen.routeName === 'events'
    ) {
        // Option 1: will close the application
        // return null;
        
        // Option 2: will keep the app open
        const newRoutes = state.routes.filter(r => r.routeName !== 'auth');
        const newIndex = newRoutes.length - 1;
        return defaultGetStateForAction(action, {
           index: newIndex,
           routes: newRoutes
        });
    }

    return defaultGetStateForAction(action, state);
};