Using Memoization

Memoization is an optimization technique that stores the results of expensive function calls and returns the cached result when the same inputs occur again. In React, memoization can help avoid unnecessary re-renders and calculations.

React.memo

React.memo is a higher-order component that you can use to memoize a component. This means that the component will only re-render if its props change.

Basic Example

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In this example, ExpensiveComponent only renders if its value prop changes, thanks to React.memo.

useMemo

useMemo is a hook that memoizes the value of a function. It is useful for memoizing derived values that are expensive to compute.

Basic Example

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In this example, expensiveCalculation only recalculates when count changes, thanks to useMemo.

useCallback

useCallback is a hook similar to useMemo, but it's designed to memoize functions. It is useful for passing functions to child components without creating new instances of the function on every render.

Basic Example

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In this example, handleClick is only recreated if count changes, thanks to useCallback.

Conclusion

Memoization is a powerful technique to optimize components and calculations in React. By using React.memo, useMemo, and useCallback, you can improve your application's performance by avoiding unnecessary re-renders and calculations. In the next topic, we will explore how to optimize resource loading in React applications.