react-spring/docs/app/routes/docs.utilities.use-isomorphic-layout-effect.mdx

---
meta:
  title: useIsomorphicLayout | React Spring
  'og:title': useIsomorphicLayout | React Spring
  'twitter:title': useIsomorphicLayout | React Spring
  description: API documentation for the useIsomorphicLayout utility hook in React Spring.
  'og:description': API documentation for the useIsomorphicLayout utility hook in React Spring.
  'twitter:description': API documentation for the useIsomorphicLayout utility hook in React Spring.
  'og:url': https://www.react-spring.dev/docs/utilities/use-isomorphic-layout-effect
  'twitter:url': https://www.react-spring.dev/docs/utilities/use-isomorphic-layout-effect
sidebar_position: 1
---

import { formatFrontmatterToRemixMeta } from '../helpers/meta'

export const meta = formatFrontmatterToRemixMeta(frontmatter)

# useIsomorphicLayoutEffect

## Usage

```tsx lines=1,9-20
import { animated, useSpring, useIsomorphicLayoutEffect } from '@react-spring/web'

const MyComponent = ({position}) => {
    const [springs, api] = useSpring(() => {
        y: 0,
        x: 0,
    }, [])

    useIsomorphicLayoutEffect(() => {
        api.start({
            from: {
                x: 0,
                y: 0,
            },
            to: {
                x: position.x,
                y: position.y,
            }
        })
    },[position])

    return <animated.div style={springs} />
}
```

## Why do we need this?

When we want to perform side-effects caused by rendering a component we need to
use [`useEffect`](https://reactjs.org/docs/hooks-reference.html#useeffect) or [`useLayoutEffect`](https://reactjs.org/docs/hooks-reference.html#uselayouteffect).
Now, the latter, `useLayoutEffect` in our opinion, is better for animations because it renders
"before the browser has a chance to paint", therefore if you want to prepare a node e.g. a div
for animation before actually animating it, it's probably better to ensure no paint happens, otherwise
you might get a sort of UI tear where the item suddenly jumps to a new position.

Neither of the above effect hooks run on the server, however, `useLayoutEffect` causes react warnings
when server-side rendering your pages (if you're using nextjs for example). So it encourages you
to move the code to `useEffect`. However, as we described above this isn't best for animations.

## What does it do?

This is where our `useIsomorphicLayoutEffect` utility hook comes in. By performing a simple (yet robust) check,
the hook correctly returns `useEffect` for server-side environments and `useLayoutEffect` for client-side
environments, thus the best of both worlds in this case.

## Typescript

The type signature will be identical to the signatures of `useEffect` and `useLayoutEffect` installed in
your project, but just to save you time, it's here below:

```ts
function useIsomorphicLayoutEffect(effect: () => (void | () => void), deps?: ReadonlyArray<unknown>)
```