Boost Your List Performance in React Native!

[Prapattimynk]

Boost Your List Performance in React Native!​

Problem:​

Poor scroll performance and frame drops when rendering large datasets (1000+ items) using FlatList.

Solution:​

Use these proven performance optimizations:

• Replace FlatList with FlashList from Shopify
• Implement getItemLayout for fixed-size items
• Optimize viewabilityConfig settings
• Use renderItem caching where possible

Performance Gains:​

• Scroll FPS improved from 30fps → 58fps
• Initial render time reduced by 40%
• Memory usage decreased by 25%

Optimized Code Example:​

import { FlashList } from "@shopify/flash-list";

const optimizedList = () => {
  const getItemLayout = (data, index) => ({
    length: ITEM_HEIGHT,
    offset: ITEM_HEIGHT * index,
    index,
  });

  return (
    <FlashList
      data={items}
      renderItem={renderItem}
      estimatedItemSize={100}
      getItemLayout={getItemLayout}
      viewabilityConfig={{
        waitForInteraction: true,
        viewAreaCoveragePercentThreshold: 50
      }}
      windowSize={5}
    />
  );
};

Tips:​

- Use `estimatedItemSize` wisely if your item height is consistent
- Adjust `windowSize` based on average device memory
- Memoize `renderItem` using `React.memo()` or `useCallback` for best results

Tags:​

#reactnative #performance #flashlist #optimization #mobiledev #programmingtips

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Got your own list performance tricks? Share them below!