useMemo is a Hook that memoizes the result of a function — it only recomputes the result when one of its dependencies changes. This optimization can avoid expensive calculations on every render.

Syntax:

const memoizedValue = useMemo(() => computeExpensiveValue(a, b), [a, b]);

When to use useMemo:

• Expensive calculations that don't need to run on every render.
• Keeping derived state that depends on props or state.
• Optimizing performance by preventing unnecessary recalculations.

⚡ Note: Don't overuse useMemo for every little calculation. Use it mainly when you face real performance bottlenecks.

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