What is the purpose of the public folder in Next.js?

The public folder (public/) in Next.js is primarily used for storing static resources such as images, font files, style sheets, and JavaScript files. These files remain static within the Next.js application, are not processed by Webpack, and are served directly by the server as files.

Main purposes include:

1. Storing images and icons: You can place all images or icons used by the website in the public folder. For example, the website's logo, navigation bar icons, and similar resources, which are typically unchanging, can be directly referenced from the public folder.

2. Storing style sheets and scripts: Although Next.js supports CSS-in-JS approaches, certain global styles or third-party library CSS/JS files can be placed in the public folder and directly linked into the project.

3. Optimizing performance: Since these files can be cached by browsers, placing them in the public folder improves website loading speed.

Application example:

Suppose we are developing an e-commerce website requiring a series of product images. We can upload these images to the public/images/ directory. In the Next.js application, we can easily reference them using relative URLs (e.g., /images/product-001.jpg) without additional configuration.

This approach simplifies resource management and referencing, enhances development efficiency, and leverages HTTP caching mechanisms to improve client access speed to static resources.