Synchronize Client and Server Rendering
- Ensure that the content generated on the server matches the client's initial render. This means all the components which use state must have consistent initial states when rendered both on the client and server.
- Use methods like `useEffect` for client-specific side-effects or DOM manipulations that should occur only after the initial render.
import React, { useState, useEffect } from 'react';
const ExampleComponent = ({ initialCount }) => {
const [count, setCount] = useState(initialCount);
useEffect(() => {
// This effect is only run on the client-side after rendering
console.log('This will only run on the client');
}, []);
return <div>Count: {count}</div>;
};
export default ExampleComponent;
Check Conditional Rendering
- Confirm that conditional renders deliver consistent HTML structures on both the client and server. Avoid conditionals based on browser-specific or dynamic runtime information during the initial render.
- In scenarios where different content must be served based on conditions (e.g., user authentication), consider using `getServerSideProps` or `getStaticProps` to fetch necessary data on the server.
import { useState } from 'react';
const AuthComponent = ({ user }) => {
const isAuthenticated = !!user;
return (
<div>
{isAuthenticated ? <span>Welcome, {user.name}</span> : <span>Please log in</span>}
</div>
);
};
// Server-side function
export async function getServerSideProps() {
// Fetch user data or authentication status
const user = await fetchUser(); // Simulate a function call
return { props: { user } };
}
export default AuthComponent;
Delay Non-Critical Content Rendering
- Postpone some parts of your UI to render exclusively on the client-side after the initial content has rendered on the server to prevent mismatches.
- Construct components where essential content is rendered server-side, while non-essential or client-specific elements use delayed rendering techniques such as dynamic import or conditional display logic.
import dynamic from 'next/dynamic';
// Dynamically import a component only on the client-side
const ClientSideComponent = dynamic(() => import('./ClientSideComponent'), {
ssr: false, // Important: disable server-side rendering for this component
});
const MyPage = () => (
<div>
<h1>Server Rendered</h1>
<ClientSideComponent />
</div>
);
export default MyPage;
Use environment-aware logic with caution
- When writing code that depends on environment-specific variables or APIs, ensure you include adequate checks or fallbacks to maintain consistency between server and client renders.
- An example of this might include features like cookies or local storage, which do not inherently belong to the server environment and should be managed client-side using `useEffect` or similar hooks.
import { useEffect, useState } from 'react';
const CookieBasedComponent = () => {
const [cookieValue, setCookieValue] = useState('');
useEffect(() => {
// This code will only run on the client as `document.cookie` isn't available on server
const cookie = document.cookie.split(';').find(cookie => cookie.trim().startsWith('myCookie='));
if (cookie) {
setCookieValue(cookie.split('=')[1]);
}
}, []);
return <div>Cookie Value: {cookieValue}</div>;
};
export default CookieBasedComponent;
