What is the difference between useLayoutEffect and useEffect?

useEffect runs asynchronously after rendering and DOM updates. It is ideal for side effects that do not affect the visual rendering, such as data fetching.

useLayoutEffect runs synchronously after rendering but before the browser "paints" the updates on the screen. It is used for reading information from the DOM, synchronously modifying the DOM, or measuring its dimensions before the user sees the result.

	useEffect	useLayoutEffect
Execution	Asynchronously	Synchronously
Timing	After rendering and DOM painting	After rendering but before DOM paint
Purpose	Side effects not affecting rendering	Reading/modifying DOM, measurements before paint
Performance	Usually better	May block rendering

When using useLayoutEffect, be cautious as it can potentially block browser repaint and cause performance issues, especially on slow devices. In most cases, it is preferable to use useEffect.