From 75b9fd0eeecf536767aae45820a0940b42c94608 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sun, 26 Apr 2026 01:33:35 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Add=20windowing=20props=20t?=
 =?UTF-8?q?o=20FlatList=20components?=
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Added `initialNumToRender`, `windowSize`, `maxToRenderPerBatch`, and `removeClippedSubviews` to `FlatList` components across `FlightScreen`, `PasswordScreen`, and `CalendarScreen` to optimize rendering performance and memory usage for long lists.

Co-authored-by: TargetMisser <52361977+TargetMisser@users.noreply.github.com>
---
 .jules/bolt.md                 |  4 ++++
 src/screens/CalendarScreen.tsx | 14 +++++++++-----
 src/screens/FlightScreen.tsx   |  4 ++++
 src/screens/PasswordScreen.tsx |  4 ++++
 4 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/.jules/bolt.md b/.jules/bolt.md
index e37d378..538a8fa 100644
--- a/.jules/bolt.md
+++ b/.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.
diff --git a/src/screens/CalendarScreen.tsx b/src/screens/CalendarScreen.tsx
index 8399c70..b186185 100644
--- a/src/screens/CalendarScreen.tsx
+++ b/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 }]}
diff --git a/src/screens/FlightScreen.tsx b/src/screens/FlightScreen.tsx
index e200b90..43aacc5 100644
--- a/src/screens/FlightScreen.tsx
+++ b/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>}
diff --git a/src/screens/PasswordScreen.tsx b/src/screens/PasswordScreen.tsx
index a9611d8..1f232a2 100644
--- a/src/screens/PasswordScreen.tsx
+++ b/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}