useEffect and useLayoutEffect are two React hooks that are used to manage side effects in a React component. Here are the differences between the two hooks:
- Timing: useEffect is executed after the browser renders the component and updates the DOM, while useLayoutEffect is executed before the browser updates the screen. This means that useLayoutEffect is more synchronous than useEffect.
- Use cases: useEffect is used for handling side effects that don't require synchronous updates, such as fetching data from an API, setting up event listeners, or updating the component's state. useLayoutEffect is used for side effects that require synchronous updates, such as measuring the dimensions of a component or manipulating the DOM.
- Performance: useEffect has a lower priority than useLayoutEffect, which means that it won't block the browser from rendering the component. This makes useEffect it more performant than useLayoutEffect in most cases. However, useLayoutEffect can be useful for avoiding layout thrashing, which occurs when the browser has to recalculate the layout of the page multiple times.
Here’s an example to illustrate the difference between useEffect and useLayoutEffect
Let’s say you have a component that needs to fetch some data from an API when it mounts:
