App.js

import { StatusBar } from 'expo-status-bar';
import { StyleSheet, Text, View} from 'react-native';
import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';
import Login from './screens/Login';
import 'react-native-gesture-handler';
import Register from './screens/Register';
import Home from './screens/Home';
import ProductDetails from './screens/ProductDetails';
import Usluge from './screens/Usluge';
import UslugeDetails from './screens/UslugeDetails';
import { Provider, useSelector } from 'react-redux';
import { store } from './redux';
const Stack = createStackNavigator();

const StackNavigator = () => {

  return (    
    <Stack.Navigator screenOptions={{header: ()=> null}}>
      <Stack.Screen name="Home" component={Home}/>
      <Stack.Screen name="ProductDetails" component={ProductDetails} />
      <Stack.Screen name="Usluge" component={Usluge} />
      <Stack.Screen name="UslugeDetails" component={UslugeDetails} />
    </Stack.Navigator>
  )
}

const AuthNavigator = () => {

  return (
    <Stack.Navigator screenOptions={{header: () => null}}>
      <Stack.Screen name="Login" component={Login}/>
      <Stack.Screen name="Register" component={Register}/> 
    </Stack.Navigator>
  )
}
const RootNavigation = () => {
  const token = useSelector(state => state.AuthReducers.token);
  return (
    <NavigationContainer>
      {
        token === null ? <AuthNavigator /> : <StackNavigator /> 
      }
    </NavigationContainer>
  );
}
export default function App() {
  return (
    <Provider store={store}>
      <RootNavigation />
    </Provider>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
});