useLayoutEffect hook

useLayoutEffect is called with a callback function and an empty dependency array ([]).
This hook runs synchronously after DOM updates but before the browser paints the screen.
In this example, it logs the current value of the input referenced by inputRef.

useLayoutEffect: This hook is similar to useEffect, but it fires synchronously after all DOM mutations. It is useful when you need to perform operations that require measurements or calculations involving the DOM, just before the browser paints. This can include updating styles, calculating dimensions, or querying DOM properties that affect layout. In this example, useLayoutEffect logs the initial value of the input field ("PEDRO") before any layout updates occur.

Why Use useLayoutEffect

Use Case: You would use useLayoutEffect when you need to ensure that your code runs synchronously after DOM mutations but before the browser paints the screen. This can be critical for operations that require precise DOM measurements or visual updates that need to be reflected immediately to avoid flickering or layout shifts.

Comparison with useEffect: If your side effect does not need to interact with the DOM synchronously or doesn't depend on the current visual state of the component, useEffect is typically more appropriate. useEffect runs asynchronously after the browser paints, making it suitable for less time-sensitive operations.

The LayoutEffectTutorial component showcases the usage of useLayoutEffect and useEffect hooks in React. useLayoutEffect is utilized for synchronously accessing and logging the initial value of an input field before layout changes, while useEffect asynchronously sets an initial value for the input field. These hooks, combined with useRef, demonstrate how to manage side effects and references in functional components effectively.