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Over the past few months, I’ve become enamoured with two popular frontend frameworks – React.js and Next.js. While both are powerful tools for building web applications, they handle rendering in very different ways. Today, I wanted to share what I’ve learned and why, in many cases, I think Next.js might be the better option.
If you’re just getting started with React and Next.js, this post should help you understand some key concepts and why many developers (especially those working on production-level apps) prefer Next.js.
What is Rendering Anyway?
Before tackling the differences, let’s quickly cover what rendering is. In web development, rendering refers to how the content of a webpage is displayed to the user. In modern web apps, especially single-page applications (SPAs), this process can happen in different ways:
Client-Side Rendering (CSR): The content is fetched and displayed in the browser using JavaScript after the initial page load. With CSR, the browser receives an almost empty HTML file at first, and JavaScript is then responsible for generating the full content dynamically.
Server-Side Rendering (SSR): The content is fetched and rendered on the server, and the fully rendered HTML is sent to the client’s browser, allowing users to see the page faster without waiting for JavaScript to load and execute.
Static Rendering: The HTML is generated at build time, and the same static content is served to all users. This is useful for pages that don’t change often, like blogs or marketing pages.
Now that we’ve covered the basics, let’s dive into how React.js and Next.js handle things differently.
How React.js Handles Rendering
By default, React apps are client-side rendered (CSR).
Initial Load: When a React app is loaded, the browser initially receives minimal HTML. The JavaScript bundle is then downloaded, React is initialized, and the app renders dynamically in the browser.
Routing: React uses client-side routing, which means that all routes are handled in the browser. When users navigate between pages, React dynamically updates the UI without refreshing the page.
Interaction: After the initial JavaScript execution, React handles all user interactions directly in the browser, updating the UI with minimal server interaction.
Pros of React’s CSR:
Dynamic UIs: React’s CSR model is great for building highly interactive applications where content changes often, such as dashboards, social media feeds, and complex forms.
Single-page Experience: Since there are no full-page reloads when navigating between views, React can create a fast and smooth experience once everything is loaded.
Cons of React’s CSR:
Slower Initial Load Time: Since React relies on JavaScript to render the UI, the user may experience a blank screen while the JavaScript bundles are downloaded and executed. This potentially longer initial load time is not ideal.
Poor search engine optimization (SEO): Search engine bots have difficulty crawling and indexing pages in a CSR app, as most of the content is rendered dynamically in the browser after the page load. Without additional configuration, this can negatively impact SEO.
Performance Issues: For larger apps, the browser has to download and execute large JavaScript bundles, which can lead to performance bottlenecks, especially for users on slower networks.
How Next.js Handles Rendering
Next.js builds on top of React, but offers more features and optimizations, particularly when it comes to rendering. It allows for both Server-Side Rendering (SSR) and Static Site Generation (SSG) in addition to CSR. This flexibility means the developer can choose how each page in the app is rendered based on its specific needs.
With SSR, Next.js fetches the data and renders the page on the server. When a user makes a request, the server returns a fully-rendered HTML page, which is then hydrated by React for interactivity. This is great for dynamic content that changes often but still needs to be SEO-friendly.
Next.js can also pre-render pages at build time, generating static HTML for pages that don’t change often. This provides the speed benefits of a static site, while still allowing dynamic behavior with React. SSG is perfect for blog posts, marketing pages, or any content that doesn’t need to change on every request.
Just like React, Next.js can also render content on the client side. The developer can decide to use CSR for certain parts of the app where it makes sense, like when interactivity is critical, and SEO isn’t a concern.
Pros of Next.js Rendering:
Faster Initial Load with SSR: By rendering pages on the server and sending fully-rendered HTML to the client, users can see the content faster without waiting for JavaScript to load. This leads to faster perceived performance and a better user experience.
SEO Benefits: Since SSR provides fully-rendered HTML to the browser, search engines can easily crawl and index the content. This means better SEO straight out of the box.
Flexibility: Next.js lets the developer choose the best rendering strategy for each page or component. You can use SSR for dynamic pages, SSG for static content, and CSR for highly interactive parts of the app. This level of control enables optimization for both performance and SEO.
Improved Performance: Since Next.js only sends the minimal JavaScript needed for a specific page, it often results in smaller JavaScript bundles and faster performance compared to a React SPA.
Cons of Next.js:
More Complexity: While Next.js adds powerful rendering options, it also introduces more complexity compared to a standard React SPA. Deciding between SSR, SSG, and CSR can sometimes be overwhelming for new developers.
Build Time for SSG: If you have a large site with hundreds or thousands of pages, generating all the static pages at build time can take some time. However, this is generally an acceptable trade-off for faster page loads in production.
Why Next.js Might Be the Better Choice
After working with both React.js and Next.js, I’d say that Next.js offers significant advantages, especially when it comes to performance, SEO, and flexibility.
React’s client-side rendering can result in slower initial page loads because users have to wait for the JavaScript to load and execute before seeing content. With Next.js, however, the initial content is rendered on the server (SSR) or pre-built during the build process (SSG), so users get to see the page almost immediately. This results in a faster, more responsive user experience.
One of the biggest pain points with React is SEO. Since React apps are mostly CSR, search engines have trouble indexing the content. This can lead to lower rankings and less visibility, which is hardly an attractive feature for clients. Next.js alleviates this problem.
With React, you’re limited to client-side rendering unless you add additional tools or libraries. Next.js, on the other hand, gives you the flexibility to use SSR, SSG, and CSR as needed. This makes it easier to optimize your app for both performance and SEO, while still leveraging React’s powerful UI-building capabilities.
Even though Next.js adds more features and options, it actually simplifies development in some ways. Features like file-based routing, API routes, and built-in SSR make it easier to build and manage complex applications without needing additional tools or configurations. Everything is neatly packaged together, reducing the need for extensive setup.
Final Thoughts
As a Junior Developer, I found it super insightful to compare React.js and Next.js, and it’s clear that while React is an amazing library for building UIs, Next.js adds a ton of value by improving performance, SEO, and offering more flexibility in how you handle rendering. If you’re building a dynamic, SEO-sensitive web app, or just want better performance, I’d highly recommend giving Next.js a try!
Thanks for reading, and I hope this article helps some of you who are also learning like me on your web development journey. Let me know if you have any thoughts, questions, or tips—I’d love to hear them! 😊
Image credit: Photo by Stanislav Kondratiev: https://www.pexels.com/photo/screen-with-code-10816120
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