What makes NextJS projects different from simple ReactJS project

Hello folks, what's up! I hope everything is going well. After a long break, I'm back to write my new article, where I'll explain how Next.js projects are different from React.js projects.

What is Next.js?

Next.js, created by Vercel, is an open-source JavaScript framework that enables the development of fast, user-friendly web applications and static websites using React. Built on Node.js and Babel, it facilitates easy server-side rendering, making it ideal for single-page applications.

Next.js provides a lightweight solution for building dynamic and static web applications, leveraging React’s capabilities. Its integration with Babel and Webpack offers an efficient out-of-the-box solution for server-side rendering of React components.

What is React.js?

React, maintained by Facebook, is a widely used front-end library that enables developers to create reusable UI components. It provides a user-friendly interface along with essential tools for routing and state management, often in conjunction with Redux and other libraries. A user interface (UI) combines HTML and JavaScript to render components of a larger application, playing a crucial role in retaining user engagement.

Next.js offers several features that distinguish it from a simple React.js project. Let’s examine the differences between them.

1. File-based Routing(Automatic Routing)

Reactjs: In a basic Reactjs project, you need to manually set up routing using libraries like react-router-dom .
Next.js: Provides automatic file-based routing. Every file inside the pages directory is automatically mapped to a route. For example, pages/index.jsx maps to the route ( / ), and pages/about.jsx maps to /about .
Example:
in React: You would need to define routes like this:

<Route path="/" component={HomePage} />
<Route path="/about" component={AboutPage} />

In Next.js, you just place files in pages/ :

pages/
├── index.js      // Maps to '/'
└── about.js      // Maps to '/about'

2. Server-side Rendering(SSR) and Static Site Generation(SSG)

React.js: React by itself only supports client-slide rendering, meaning the content is generated in the browser. You need additional setups like ReactDOMserver or third-party libraries to implement server-side rendering.
Next.js: Supports both Server-Side Rendering (SSR) and Static Site Generation (SSG) out of the box. You can pre-render pages on the server, improving SEO and initial load times.

Example:

Static Generation: Pre-builds HTML at build time

    export async function getStaticProps() {
    const data = await fetchData();
    return { props: { data } };
  }

Server-Side Rendering: Fetches data on each request.

    export async function getServerSideProps() {
      const data = await fetchData();
      return { props: { data } };
    }

3. API Routes

React.js: React doesn't handle backend logic directly. You need to set up an API server (like Express.js or a third-party backend) to handle server-side requests.
Next.js: You can create API routes within the same project. These routes are placed in the pages/api directory and each file corresponds to an API endpoint.

Example:

In Next.js, create an API route:

   pages/api/hello.js

   export default function handler(req, res) {
    res.status(200).json({ message: 'Hello, World!' });
  }

You can access it via http://localhost:3000/api/hello.

4. Built-in CSS and Sass Support

React.js: React does not come with built-in CSS support. You typically need to set up tools like Webpack, Sass, or use third-party libraries for CSS.
Next.js: It comes with built-in support for CSS and Sass. You can import CSS and Sass files directly without additional configuration.

Example:

import './styles.css';  // Regular CSS
import './styles.scss'; // Sass

5. Optimized for SEO

React.js: React apps typically rely on client-side rendering, which can hinder SEO because search engines might not index dynamic content rendered on the client.
Next.js: By default, Next.js supports server-side rendering, which means pages are pre-rendered on the server, making it easier for search engines to crawl and index content.

6. Image Optimization

React.js: You would need third-party libraries or manual configuration to optimize images.
Next.js: Includes a built-in next/image component that automatically optimizes images, lazy loads them, and provides responsive sizes.

Example:

import Image from 'next/image';
import myImage from '../public/myImage.jpg';

function MyPage() {
  return (
    <div>
      <h1>My Page</h1>
      <Image src={myImage} alt="A beautiful image" width={500} height={300} />
    </div>
  );
}

7. Static File Serving

React.js: You must manually configure static file serving or use a separate file server (e.g., Express) for things like images, fonts, etc.
Next.js: Static files can be placed in the public/ folder and are automatically served at the root URL.

Example:

Place images in the public folder:
```
   public/
  └── my-image.jpg
```

You can access it as /my-image.jpg in your app.

8. Dynamic Routing

React.js: Dynamic routing in React is typically handled via react-router-dom and requires manual configuration to handle dynamic segments (e.g., /post/:id).
Next.js: Supports dynamic routing by using file naming conventions. Files are named with brackets ([param]), and Next.js automatically maps these to dynamic routes.

Example:

In Next.js:
```
  pages/
  └── posts/[id].js // Dynamic route for individual posts
```
The file pages/posts/[id].js would match routes like /posts/1, /posts/2, etc.

9. Built-in TypeScript Support

React.js: You need to configure TypeScript manually in a React project.
Next.js: Next.js comes with built-in TypeScript support. You only need to install TypeScript and start using it.

Example:

npm install --save-dev typescript @types/react @types/node

Once you create a .ts or .tsx file, Next.js automatically detects TypeScript.

10. Deployment and Performance Optimizations

React.js: React doesn't offer built-in optimizations for production deployment. You need to configure optimizations like code splitting, lazy loading, etc.
Next.js: Next.js optimizes the application automatically during the build process, providing features like automatic code splitting, static export, and server-side rendering.

When To use React.js?

Use React.js when

You want complete control and flexibility over the app structure.
You’re building a simple SPA or dynamic frontend.
Your project doesn’t require server-side rendering or SEO optimization.

Use Next.js When

You want a complete solution with backend and frontend capabilities.
Your app needs features like SSR, SSG, or SEO optimization
You prefer opinionated defaults for faster and easier development.
You’re building a production-ready application.

Next.js extends React by offering many built-in features like routing, server-side rendering, static generation, and API routes, making it suitable for building production-grade applications with better performance and SEO.