Nextjs for Everyone — with Some Basic React Knowledge

Next.js has rapidly become one of the most popular tools for building modern web applications. But what exactly is Next.js, and why are so many developers excited about it? In this in-depth guide, we‘ll explore the key features and benefits of Next.js from the perspective of a professional full-stack developer.

What is Next.js?

Next.js is an open-source React framework created by Vercel (formerly ZEIT). It allows developers to easily create server-side rendered (SSR) and statically generated (SSG) web applications using React.

Out of the box, Next.js provides a powerful set of features on top of React, including:

• Automatic server-side rendering and code splitting
• Simple page-based routing with file system routing
• API routes for creating backend endpoints
• Static file serving
• CSS-in-JS and CSS module support
• TypeScript support
• Smart bundling and prefetching
• Easy deployment

These features address many of the common pain points of building React applications, such as configuring build tools, handling server-side rendering, and optimizing for performance.

Why Use Next.js?

So why would you choose to use Next.js over plain React or another framework like Vue or Angular? Let‘s look at some of the key benefits and use cases for Next.js.

1. Server-Side Rendering

One of the biggest advantages of Next.js is its support for server-side rendering out of the box. SSR is the process of rendering your React components on the server and sending the resulting HTML to the browser.

SSR provides several key benefits over client-side only rendering:

• Better SEO: Search engines can more easily crawl and index your site‘s content since it is rendered on the server. This is critical for any website that relies on organic search traffic.

• Faster initial load times: With SSR, the server sends a fully rendered HTML page to the client on the initial load. The user can see the page content immediately while the JavaScript bundles load in the background. This provides a better user experience, especially on slower networks.

• Social media sharing: SSR ensures that social media previews display the full content of your page, rather than just the bare-bones HTML shell that you see with client-side only apps.

Here‘s a simple example of an SSR page in Next.js:

function HomePage() {
  return 
}

export default HomePage

Any page component in the pages directory will be automatically server-side rendered by Next.js. No extra configuration needed!

2. Static Site Generation

In addition to SSR, Next.js also supports static site generation (SSG). With SSG, Next.js generates static HTML files for each page at build time. These files can then be served directly from a CDN for maximum performance.

SSG provides the best of both worlds – the fast initial loads of a static site, with the rich interactivity of a React app. Some advantages of SSG include:

• Blazing fast performance: Static files can be served from a global CDN instantly. According to Google, 53% of mobile users abandon sites that take over 3 seconds to load. With SSG, you can get load times in the milliseconds.

• Cheap and easy to scale: Serving static files is much cheaper and easier to scale than dynamic SSR pages, since they can be cached and don‘t require a running server.

• Better developer experience: With SSG, you can build and test your entire site locally without needing to run a server. And you can still use React components and libraries to make your site dynamic.

To use SSG in Next.js, you export an async function called getStaticProps from your page component:

function BlogPost({ post }) {
  return (
    <div>

      <p>{post.content}</p>
    </div>
  )
}

export async function getStaticProps() {
  const post = await getPostFromDatabase()

  return {
    props: {
      post,
    },
  }
}

export default BlogPost

Next.js will call getStaticProps at build time and use the returned props to pre-render the page. You can query a database, fetch data from an API, or read from the file system in this function.

3. Simple Routing

Next.js uses a file-based routing system that feels very natural coming from React. Pages are associated with a route based on their filename:

• pages/index.js is associated with the / route
• pages/about.js with /about
• pages/blog/[slug].js with /blog/:slug (dynamic route)
• pages/post/[...all].js with /post/* (catch-all route)

To link between pages, Next.js provides a <Link> component that you can use to perform client-side routing:

import Link from ‘next/link‘

function Header() {
  return (
    <nav>
      <Link href="/">
        <a>Home</a>
      </Link>
      <Link href="/about">
        <a>About</a>
      </Link>
      <Link href="/blog/hello-world">
        <a>Blog Post</a>
      </Link>
    </nav>
  )
}

export default Header

4. API Routes

Next.js allows you to create API endpoints as Node.js serverless functions, right inside your Next app! This means you can write server-side code to handle things like form submissions, database queries, and third-party integrations without needing a separate backend service.

To create an API route, add a file in pages/api that exports a request handler:

export default function handler(req, res) {
  if (req.method === ‘POST‘) {
    // Process a POST request
  } else {
    // Handle any other HTTP method
  }
}

API routes can be deployed as Serverless Functions (also known as Lambdas). Next.js versions 8 and above support API routes out of the box with Vercel, a platform for deploying static and serverless applications.

5. Performance Features

Next.js has several features dedicated to making your application as performant as possible out of the box. These include:

• Code splitting and bundling: Next.js automatically splits your application‘s JavaScript into manageable chunks using dynamic import(). This ensures that only the code needed for the initial route is loaded, with additional chunks loaded on-demand as the user navigates around.

• Prefetching: Next.js has built-in support for prefetching pages in the background. It will automatically prefetch the JavaScript code for other pages linked with the <Link> component. This makes navigating between pages feel near-instant!

• Image optimization: The Next.js <Image> component automatically optimizes images, so they are responsive, sized correctly, and served in modern formats like WebP when the browser supports it. Images are lazy-loaded by default, meaning they only load when they come into view.

All these performance optimizations are implemented under the hood, with no configuration needed by the developer. This means you can focus on building your app, and Next.js will take care of making it fast.

6. Developer Experience

Next.js has an excellent developer experience that makes creating React apps fun and productive. Some of the developer-friendly features include:

• Hot code reloading: Next.js automatically applies code changes in the browser as you edit files during development, preserving component state.

• Automatic TypeScript configuration: Next.js has built-in TypeScript support and will automatically create a tsconfig.json file for you.

• ESLint integration: Next.js comes with a built-in ESLint configuration that helps you follow best practices and catch potential bugs as you code.

• Extensible plugin architecture: Next.js has a powerful plugin system that allows you to hook into the build pipeline and extend the framework with your own custom features.

• Vibrant community and ecosystem: Next.js has a huge community of developers and an extensive ecosystem of plugins, starters, and example projects to help you get up and running quickly.

In addition to its developer-friendly defaults, Next.js is also highly customizable. You can override the Babel, Webpack, and PostCSS configs, add environment variables, customize the <head> of each page, and more.

Use Cases for Next.js

So what kind of applications is Next.js good for? Here are some common use cases where Next.js shines:

• Marketing sites and landing pages: Next.js static site generation makes it easy to build blazing-fast marketing sites that are easy to scale and cheap to host. You can even use your React components to build the pages!

• Ecommerce sites: Next.js server-side rendering and API routes make it a great fit for ecommerce sites that need to be SEO-friendly and integrate with backend systems.

• SaaS applications: Next.js is well-suited for building complex, client-heavy SaaS applications. Its automatic code splitting and prefetching features make it easy to build fast, responsive UIs.

• Mobile web apps: Next.js is a great choice for building progressive web apps (PWAs) and mobile web apps. Its static file serving and offline support make it possible to build app-like experiences in the browser.

• Desktop applications with Electron: You can use Next.js to build the UI for your Electron app, and take advantage of its SSR and code splitting features to create a fast, responsive desktop application.

Of course, this is just a sampling of what you can build with Next.js. Its flexibility and feature-richness make it a good fit for any situation where you need to create a high-performance, production-ready React application.

Learning Next.js

If you‘re already familiar with React, learning Next.js should be a relatively straightforward process. The Next.js documentation is excellent, with an in-depth tutorial that covers all the basics.

To dive deeper into Next.js, I recommend checking out the following resources:

• Mastering Next.js: A comprehensive video course by Lee Robinson, a core maintainer of Next.js.
• Next.js Conf: The official Next.js conference, with talks from the Next.js team and community members.
• Next.js GitHub repository: The source code and issue tracker for Next.js. A great place to learn how Next.js works under the hood.
• Next.js Discord community: A friendly community of Next.js developers, with channels for general discussion, help, and showcasing projects.

There are also many great articles, tutorials, and videos available on platforms like DEV, Medium, and YouTube. A quick search for "Next.js tutorial" will turn up plenty of high-quality learning materials.

The Future of Next.js

As of December 2022, Next.js is on version 13 and shows no signs of slowing down. The Next.js team is constantly working on new features and improvements, with a focus on making the framework even more performant, flexible, and easy to use.

Some of the recent and upcoming additions to Next.js include:

• App directory (beta): A new way to structure your application code that enables powerful features like nested layouts, server components, and more. (Version 13)
• Turbopack (alpha): An incremental bundler that aims to be a faster, Rust-based alternative to Webpack. (Version 13)
• Middleware: Allows you to run code before a request is completed, for use cases like authentication, logging, and more. (Version 12)
• React Server Components: Allows you to render components on the server and send them to the client as HTML, for improved performance and simplicity. (Experimental)

One thing is clear: Next.js is committed to staying on the cutting edge of web development and providing the best possible developer experience for building React applications. As a Next.js developer, you can expect a steady stream of new features and improvements in the coming years.

Conclusion

Next.js is a powerful, flexible framework that makes it easy to build high-performance React applications. Its combination of server-side rendering, static site generation, and other performance optimizations provide a great foundation for any web app.

Whether you‘re building a simple landing page or a complex application, Next.js has the tools and features you need to succeed. Its excellent developer experience, comprehensive documentation, and supportive community make it a pleasure to work with.

If you‘re a React developer looking to take your skills to the next level, I highly recommend giving Next.js a try. With its intuitive APIs and useful defaults, you‘ll be building production-ready apps in no time!