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Hook that returns the previous value.

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Aabonello
Last edited Aug 24, 2021
Created on Dec 30, 2021

This example demonstrates a custom React hook that retains and returns the previous value of a prop or state variable between renders. The hook uses `useRef` to store the current value and `useEffect` to update the ref whenever the value changes, while returning the ref’s previous value from the render. It is written in TypeScript and relies on React’s `useEffect` and `useRef` APIs, showing a common pattern for comparing current and prior values in component logic.

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