In this lecture, Harkirat introduces Next.js, a React framework that simplifies the development of server-rendered React applications. He highlights the benefits of Next.js over traditional React applications, such as built-in server-side rendering, API routes, file-based routing, and optimizations for bundle size and static site generation. Harkirat addresses the waterfalling issue, explores Next.js offerings, and guides through project setup, file structure, routing, layouts, and the use of client components.

Pre-requisites

Before diving into Next.js 14, it's essential to have a solid understanding of basic frontend development concepts and React. Here's what you need to know:

1. HTML, CSS, and JavaScript: Familiarize yourself with the fundamentals of web development, including HTML for structuring content, CSS for styling, and JavaScript for adding interactivity.
2. React Basics: Learn the core concepts of React, such as components, state, props, and lifecycle methods. Understand how to create simple React applications and manage component hierarchies.

import React, { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0);

  const incrementCount = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <h1>Count: {count}</h1>
      <button onClick={incrementCount}>Increment</button>
    </div>
  );
}

This is a simple React component that demonstrates state management and event handling.

Next.js Introduction

Next.js is a popular React framework that simplifies the development of server-rendered React applications. It was introduced to address some of the challenges and inconveniences faced in traditional React development.

Problems Addressed by Next.js

1. Separate Backend Project for API Routes: In a traditional React project, you often need to maintain a separate backend project for handling API routes and server-side logic. Next.js provides a built-in API routes feature, allowing you to handle API requests directly within your Next.js application.
2. Routing: React doesn't provide out-of-the-box routing capabilities, requiring the use of third-party libraries like React Router. Next.js comes with a built-in file-based routing system, making it easier to manage routes and handle navigation.
3. SEO Optimization: React applications are rendered on the client-side by default, which can negatively impact search engine optimization (SEO). Next.js supports server-side rendering (SSR) and static site generation (SSG), ensuring that your application is SEO-friendly and optimized for search engines.
4. Waterfalling Problem: In traditional React applications, the entire application bundle needs to be downloaded before the application can start rendering, leading to a "waterfalling" effect. Next.js addresses this issue by supporting code splitting and lazy loading, allowing for faster initial load times and improved performance.

React Server Components (RSC)

While React was initially not optimized for SEO, the introduction of React Server Components (RSC) in Next.js 13 has improved this aspect. RSC allows you to render components on the server, providing better SEO and performance benefits. We'll discuss RSC in more detail later in this guide.

In the next sections, we'll explore these problems and the solutions provided by Next.js in greater depth, along with code examples and practical implementations.