Network errors, empty states, and edge cases show user-friendly messages

Reviewers deliberately test on degraded networks and with edge-case data. Empty catch blocks (CWE-390) that swallow errors produce blank white screens — a visible failure that signals low quality and triggers rejection under Apple's guideline 2.1. ISO 25010:2011 fault-tolerance requires systems to continue operating under abnormal conditions. Beyond rejection risk, raw error messages ({error.message}) leak implementation details and destroy user trust. A screen that shows nothing when the network is bad is indistinguishable from a bug.

Implement all four UI states for every data-fetching screen.

// src/screens/FeedScreen.tsx
export default function FeedScreen() {
  const { data, isLoading, error, refetch } = useFeed();

  if (isLoading) return <ActivityIndicator />;
  if (error) return (
    <View style={styles.center}>
      <Text>Couldn't load your feed.</Text>
      <Button title="Try again" onPress={refetch} />
    </View>
  );
  if (!data?.length) return <EmptyState message="Nothing here yet — check back soon." />;
  return <FlatList data={data} renderItem={renderItem} />;
}

Never render {error.message} or {error.toString()} directly. Test every screen with airplane mode enabled on the simulator before submission.