People Are Missing the Point When Abusing Next.js ‘use client’ - Here’s Why

The release of Next.js has been a game-changer for web developers, offering an unparalleled blend of server-side rendering (SSR), static site generation (SSG), and client-side capabilities. However, one particular feature, the use client directive, has become a point of contention within the community. Many developers are misusing or overusing it without fully understanding its implications, and this is causing avoidable issues in their applications.

Let’s explore what use client is, why it exists, and the pitfalls of abusing it.

What Is use client?

In Next.js, React’s server components are the default. This allows for faster page loads, reduced JavaScript payloads, and better overall performance. However, not all components can be server components. For example, components that:

• Use useState or useEffect
• Access browser-specific APIs like localStorage
• Rely on event listeners for interactivity

These must be designated as client components, and this is where the use client directive comes into play.

By adding use client at the top of a file, you tell Next.js that the component should be rendered on the client side.

The Problem: Overuse of use client

The flexibility of use client is both a blessing and a curse. Some developers mistakenly add it to every file, thinking it’s a harmless or even beneficial default. Here’s why that’s a mistake:

1. Performance Degradation: Server components are optimized for performance. By turning a component into a client component unnecessarily, you:

   • Increase the JavaScript bundle size.
   • Require hydration on the client, which can slow down rendering.
   • Lose the benefits of server-side caching.

2. Complexity in Data Fetching: Server components naturally integrate with data-fetching methods, such as getServerSideProps or getStaticProps. By switching to client components, you might have to re-implement complex fetching logic using hooks like useEffect.

3. Missed Opportunities for Simplicity: Many components don’t need interactivity or browser-specific APIs. Making them client components adds unnecessary complexity and resource usage.

Why Does This Happen?

The misuse of use client often stems from misunderstanding or a lack of clarity around when it’s needed. Developers transitioning from older React paradigms, where everything ran on the client, might be tempted to default to client components out of habit.

Additionally, debugging can sometimes lead developers to slap use client on components in an attempt to fix unrelated issues, creating a band-aid solution rather than addressing the root cause.

Best Practices for Using use client

To avoid falling into the trap of overusing use client, consider these guidelines:

1. Default to Server Components: Only use use client when absolutely necessary. Ask yourself, “Does this component really need to run on the client?”

2. Leverage Composition: If part of a component requires client-side functionality, isolate that logic into a smaller client component and keep the rest on the server. For example:

   // ParentComponent.jsx
   export default function ParentComponent({ data }) {
       return (
           <div>
               <ServerComponent data={data} />
               <ClientComponent />
           </div>
       );
   }
   
   // ClientComponent.jsx
   "use client";
   
   export default function ClientComponent() {
       const [count, setCount] = useState(0);
       return <button onClick={() => setCount(count + 1)}>Click me</button>;
   }

3. Audit Your Codebase: Periodically review your components. Remove unnecessary use client directives to regain performance and simplify your app.

4. Stay Educated: Keep up with the latest updates and guidelines from the Next.js documentation. The framework evolves rapidly, and staying informed can save you headaches.

Conclusion

The use client directive is a powerful tool in the Next.js ecosystem, but with great power comes great responsibility. Misusing it undermines the very advantages that Next.js provides, leading to bloated applications and degraded performance.

By understanding when and why to use use client, you can build applications that are not only fast and efficient but also easier to maintain. So, the next time you’re tempted to reach for use client, stop and ask yourself: Is this really necessary? Chances are, the answer will save you and your users from unnecessary trouble.