use-focus-effect-example.tsx

import { useCallback } from 'react';
import { useNavigation, NavigationProp, useFocusEffect } from '@react-navigation/native';

function delay(ms: number) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

function ScreenA() {
  const navigation = useNavigation<NavigationProp<any>>();

  useFocusEffect(
    useCallback(() => {
      const timeoutId = setTimeout(() => {
        // Schedule a navigation 5 seconds after this screen is focused.
        navigation.navigate('ScreenB');
      }, 5000);
      
      return () => {
        // If user leaves the screen, cancel the scheduled navigation.
        clearTimeout(timeoutId);
      };
    }, [navigation])
  );

  return <></>;
}