22 Minifying in Next.js

Minifying is an important process in web development where code files are reduced in size to improve load times. Next.js provides built-in support for minifying JavaScript and CSS files, which contributes to faster load times and better performance.

22.1 Automatic minimization

In Next.js, minification is performed automatically when the application is built for production. This process includes:

  1. JavaScript Minimization: Next.js uses Terser, a popular JavaScript minimizer, to shrink the JavaScript code.

  2. CSS Minimization: CSS files are minimized by using tools like Clean-CSS or cssnano.

22.2 Custom configuration of the minimization

Although Next.js applies minimization by default, developers can customize the minimization configuration via the next.config.js file if there are specific requirements.

22.2.1 Example configuration:

module.exports = {
  webpack(config, { dev }) {
    if (!dev) {
      config.optimization.minimizer = [
        // Custom minimizer configuration
      ];
    }
    return config;
  },
};

22.3 Advantages of minimization

  1. Reduced file size: Minification removes unnecessary characters such as spaces, line breaks and comments, reducing file size.

2 Faster loading times: Smaller files result in faster website load times.

3 Improved performance: Faster load times contribute to a better user experience and potentially a higher SEO ranking position.

4 Increased efficiency: Minification can be used in conjunction with other optimization techniques such as code splitting and compression to further increase efficiency.

22.4 Exercise: Creating a Next.js application with minimization

22.4.1 Goal

Develop a simple Next.js application with a start page and an additional page. The application should automatically use minimized JavaScript and CSS files in the production build.

22.4.2 Task

  1. Create a new Next.js application: Use create-next-app to start a new project.

  2. Add two pages: A home page (index.js) and an “about us” page (about.js).

3 Stylize the pages: Use CSS or CSS-in-JS to stylize the pages.

4 Perform a production build: Build the application for production and verify that the JavaScript and CSS files have been minified.