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.agents/skills/vercel-react-native-skills/rules/ui-scrollview-content-inset.md

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+---
+title: Use contentInset for Dynamic ScrollView Spacing
+impact: LOW
+impactDescription: smoother updates, no layout recalculation
+tags: scrollview, layout, contentInset, performance
+---
+
+## Use contentInset for Dynamic ScrollView Spacing
+
+When adding space to the top or bottom of a ScrollView that may change
+(keyboard, toolbars, dynamic content), use `contentInset` instead of padding.
+Changing `contentInset` doesn't trigger layout recalculation—it adjusts the
+scroll area without re-rendering content.
+
+**Incorrect (padding causes layout recalculation):**
+
+```tsx
+function Feed({ bottomOffset }: { bottomOffset: number }) {
+  return (
+    <ScrollView contentContainerStyle={{ paddingBottom: bottomOffset }}>{children}</ScrollView>
+  );
+}
+// Changing bottomOffset triggers full layout recalculation
+```
+
+**Correct (contentInset for dynamic spacing):**
+
+```tsx
+function Feed({ bottomOffset }: { bottomOffset: number }) {
+  return (
+    <ScrollView
+      contentInset={{ bottom: bottomOffset }}
+      scrollIndicatorInsets={{ bottom: bottomOffset }}
+    >
+      {children}
+    </ScrollView>
+  );
+}
+// Changing bottomOffset only adjusts scroll bounds
+```
+
+Use `scrollIndicatorInsets` alongside `contentInset` to keep the scroll
+indicator aligned. For static spacing that never changes, padding is fine.