Memoization

React Native 6 min min read Updated: Aug 03, 2026 Intermediate
Memoization
Intermediate Topic 6 of 18

Memoization

Memoization is a technique for caching the results of expensive computations or function references, preventing unnecessary recalculations and re-renders in React Native applications.

What is Memoization?

Memoization stores the result of a computation and returns the cached result on subsequent calls with the same inputs, rather than recalculating it every time.

Memoizing Expensive Calculations

javascript const total = useMemo(() => { return items.reduce((sum, item) => sum + item.price, 0); }, [items]);

Memoizing Components

javascript const ProductCard = React.memo(({ product }) => { return {product.name}; });

Memoizing Function References

javascript const handlePress = useCallback(() => { navigation.navigate('Details', { id: item.id }); }, [item.id, navigation]);

When Memoization Helps

Memoization is most beneficial for expensive calculations, components that render frequently with the same props, or preventing unnecessary re-renders of memoized child components.

When Memoization Can Hurt Performance

Overusing memoization for simple, cheap computations or components that rarely re-render can actually add unnecessary overhead, since the memoization check itself has a small performance cost.

Memoization with Redux Selectors

Libraries like Reselect apply memoization principles to Redux selectors, ensuring derived state calculations only re-run when their specific input state actually changes.

Conclusion

Understanding when and how to apply memoization through useMemo, useCallback, and React.memo allows you to optimize React Native performance strategically, without over-engineering simple components unnecessarily.

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