Using useMemo for Caching and Optimizing Performance

useMemo is a React Hook that helps optimize performance by memoizing (caching) the result of a function so that it doesn't need to be recalculated on every render.

When to Use useMemo

Computations: When you have a computation that’s expensive and its result doesn’t change often, you can use useMemo to avoid recalculating it on every render.

Stable References: When passing objects or arrays as props to child components, useMemo can help ensure that the references to these props remain stable, avoiding unnecessary re-renders of child components.

Example:

import React, { useMemo } from 'react';

function MyComponent({ items }) {
  // This computation will only be recalculated if `items` changes
  const sumItems = useMemo(() => {
    return items.reduce((sum, item) => sum + item.value, 0);
  }, [items]);

  return <div>Total Value: {sumItems}</div>;
}

In this example, sumItems will only be recalculated when items changes, improving performance by avoiding unnecessary calculations on every render.

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