JAVASCRIPT
Safely Use `useLayoutEffect` in SSR Environments with `useIsomorphicLayoutEffect`
Implement `useIsomorphicLayoutEffect` to conditionally use `useLayoutEffect` on the client-side and `useEffect` on the server-side, preventing SSR warnings in React.
import { useEffect, useLayoutEffect } from 'react';
// Helper to determine if we are in a browser environment
const isBrowser = typeof window !== 'undefined';
// Conditionally use useLayoutEffect on the client, useEffect on the server
const useIsomorphicLayoutEffect = isBrowser ? useLayoutEffect : useEffect;
// Example Usage:
function MyComponentWithEffect() {
useIsomorphicLayoutEffect(() => {
// This code runs synchronously after all DOM mutations.
// On the server, it runs asynchronously like useEffect.
console.log('Isomorphic effect executed!');
return () => {
console.log('Isomorphic effect cleanup!');
};
}, []); // Run once on mount/unmount
return <div>Check console for effect messages.</div>;
}
How it works: `useLayoutEffect` runs synchronously after DOM mutations, ideal for measuring DOM elements or modifying the DOM before painting. However, it causes warnings during Server-Side Rendering (SSR) due to the absence of a DOM. `useIsomorphicLayoutEffect` addresses this by conditionally using `useLayoutEffect` in a browser environment and falling back to `useEffect` on the server, ensuring safe and consistent behavior across client and server.