Converting className to CSS Modules in Next.js

Описание: Discover how to seamlessly convert your `className` attributes in Next.js using CSS Modules in this easy-to-follow guide.
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This video is based on the question https://stackoverflow.com/q/69441038/ asked by the user 'MarioG8' ( https://stackoverflow.com/u/13705979/ ) and on the answer https://stackoverflow.com/a/69462762/ provided by the user 'MarioG8' ( https://stackoverflow.com/u/13705979/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Converting className to CSS Modules in Next.js: A Simple Guide

When developing with Next.js, many developers encounter situations where they want to use CSS Modules instead of global styles. This can be a little tricky, especially when it comes to converting the className attributes in your components. If you've been scratching your head wondering how to make this transition easily, you're in the right place!

Understanding the Problem

In Next.js, using global CSS files can lead to potential conflicts and challenges with style encapsulation. CSS Modules provide a fantastic solution to this issue by scoping styles locally to the component, helping to prevent clashes in class names across the application.

When you want to convert existing className usages to leverage CSS Modules, it's important to do it correctly to avoid runtime errors. Consider the following code snippet illustrating a button component that uses global styles:

[[See Video to Reveal this Text or Code Snippet]]

In the above implementation, class names are directly referenced as strings, which works well with global styles but is not suitable for CSS Modules.

The Solution

To convert your styles to CSS Modules effectively, follow the steps outlined below:

1. Create a CSS Module File

First, ensure that you have a CSS Module file. This is usually named with the following convention: ComponentName.module.css. For our button example, you might have Button.module.css.

2. Import the CSS Module

Next, you need to import the CSS Module into your component. Here's how it should look:

[[See Video to Reveal this Text or Code Snippet]]

3. Update the className Property

The critical step is in changing your className assignment. Instead of referencing the class names as strings, you'll reference them through the styles object generated from the CSS Module. Here's how to do it:

[[See Video to Reveal this Text or Code Snippet]]

Breakdown of the Updated Code:

${styles.btn}: This directly points to the defined btn style in your Button.module.css file.

${styles[checkButtonStyle]}: Accesses the button style dynamically based on the variable checkButtonStyle.

${styles[checkButtonSize]}: Similarly grabs the button size style based on the variable checkButtonSize.

Example Implementation

Here’s how a complete Button component using CSS Modules might look like:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Converting your className attributes to use CSS Modules in Next.js doesn’t have to be a daunting task. By following the steps outlined in this guide, you can effectively manage styles in a clean and maintainable way.

A special thanks to -juliomalves for the insightful guidance that made this task easier. Happy coding, and enjoy the benefits of scoped styles with CSS Modules!