⚡ Bolt: Optimize FlatList rendering with windowing props

.jules/bolt.md

@@ -1,3 +1,7 @@
 ## 2024-04-13 - Missing React.memo for FlatList Items
 **Learning:** The React Native FlatList components in this codebase frequently render unmemoized inline items (like `ContactRow`, `PasswordRow`, etc.), causing unnecessary re-renders of the entire list when individual state changes.
 **Action:** Always wrap long list item components in `React.memo()` to prevent cascading re-renders and improve FlatList scrolling performance.
+
+## 2026-04-26 - Missing FlatList Windowing Props
+**Learning:** FlatList components in React Native were rendering without windowing props, which can lead to poor performance on long lists due to excessive memory usage and rendering overhead.
+**Action:** Always add windowing props (`initialNumToRender`, `windowSize`, `maxToRenderPerBatch`, etc.) to `FlatList` components to optimize memory and rendering performance.

src/screens/CalendarScreen.tsx

@@ -663,11 +663,15 @@ export default function CalendarScreen() {
                 <Text style={[s.stepLabel, { color: colors.textSub }]}>
                   {t('calPickName')} ({parsedSchedule.employees.length} trovati)
                 </Text>
-                <FlatList
-                  data={parsedSchedule.employees}
-                  keyExtractor={(_, i) => String(i)}
-                  style={{ maxHeight: 400 }}
-                  nestedScrollEnabled
+                <FlatList
+                  data={parsedSchedule.employees}
+                  keyExtractor={(_, i) => String(i)}
+                  style={{ maxHeight: 400 }}
+                  nestedScrollEnabled
+                  initialNumToRender={15}
+                  windowSize={5}
+                  maxToRenderPerBatch={10}
+                  removeClippedSubviews={true}
                   renderItem={({ item }) => (
                     <TouchableOpacity
                       style={[s.nameRow, { borderColor: colors.border }]}

src/screens/FlightScreen.tsx

@@ -919,6 +919,10 @@ export default function FlightScreen() {
           data={currentData}
           keyExtractor={(item, i) => item.flight?.identification?.id || String(i)}
           renderItem={renderFlight}
+          initialNumToRender={10}
+          windowSize={5}
+          maxToRenderPerBatch={10}
+          removeClippedSubviews={true}
           contentContainerStyle={{ padding: 16, paddingBottom: 96 }}
           refreshControl={<RefreshControl refreshing={refreshing} onRefresh={() => { setRefreshing(true); fetchAll(); }} tintColor={colors.primary} />}
           ListEmptyComponent={<Text style={{ textAlign: 'center', marginTop: 40, color: '#9CA3AF', fontSize: 15 }}>{t('flightNoFlights')}</Text>}

src/screens/PasswordScreen.tsx

@@ -307,6 +307,10 @@ export default function PasswordScreen() {
       <FlatList
         data={entries}
         keyExtractor={item => item.id}
+        initialNumToRender={15}
+        windowSize={5}
+        maxToRenderPerBatch={10}
+        removeClippedSubviews={true}
         renderItem={({ item }) => (
           <PasswordRow
             item={item}