Nextjs Styling Components With Css Modules And Styled Jsx Complete Guide

Top 10 Questions and Answers on Next.js Styling Components with CSS Modules and Styled JSX

Answer: In Next.js, CSS Modules are a styling method that allows you to write CSS in a way that it's scoped locally to the component, avoiding global style conflicts. You can use them by creating a CSS file with the .module.css or .module.scss/.module.sass extension if using SCSS/SASS. The styles defined in these files are only applied to the component where they're imported.

2. How do I use CSS Modules in Next.js?

Answer: To utilize CSS Modules, simply create a file with a .module.css suffix. For example, Button.module.css. Import it into your component and apply the styles by referencing the class names as properties of the imported object. Here’s how:

import styles from './Button.module.css';

function Button() {
  return <button className={styles.button}>Click me</button>
}

The className would then correspond to the classes from the Button.module.css file.

3. Can I use variables or mixins in CSS Modules?

Answer: If you're using CSS Modules, you can take advantage of variables and mixins provided by preprocessors like SCSS or SASS. First, ensure that you've installed necessary loaders for SCSS (e.g., sass) and configured your build process if not already done. Then, you can define variables or mixins in SCSS just as you would in a regular SCSS file.

// Button.module.scss
$primaryColor: #4285f4;

@mixin button-base {
  padding: 10px 20px;
  border-radius: 5px;
}

.button {
  @include button-base;
  background-color: $primaryColor;
}

4. What is Styled JSX in Next.js?

Answer: Styled JSX is an inline-style methodology that lets you write styles within your JavaScript/JSX in a way that is scoped to the component. You just need to declare a <style jsx> tag in the component. It is enabled by default in Next.js, making it easy to get started without additional configuration.

5. How do I use Styled JSX in Next.js?

Answer: Using Styled JSX is as simple as adding a <style jsx> block inside a JSX component. Styles declared here are automatically scoped to this specific component. Here's a basic example:

function Hello() {
  return (
    <div>
      Hello world
      <p>This is a styled paragraph.</p>

      <style jsx>{`
        div {
          color: blue;
        }
        p {
          font-size: 14px;
        }
      `}</style>
    </div>
  )
}

Note: The style blocks only affect the scope of the current component.

6. Can Styled JSX handle global styles?

Answer: While Styled JSX is primarily for local scoping, you can create global styles by setting global attribute in the <style> tag. This will ensure that the styles affect the entire document, not just the component.

<style jsx global>{`
  body {
    background-color: lightgray;
  }
`}</style>

7. What are the advantages and disadvantages of using CSS Modules over Styled JSX in Next.js?

Answer: Advantages of CSS Modules include better tooling support, reusability, separation of concerns, and easier debugging due to scoped selectors. Disadvantages might be additional configuration for SCSS, more files, and potential overhead due to module resolution.

Styled JSX, on the other hand, has its own advantages such as writing styles next to components, no need for imports/exports, and automatic scope management. However, disadvantages can include verbosity, complex debugging (due to how styles are scoped dynamically), and lack of reusability.

8. How can I use both CSS Modules and Styled JSX together in Next.js?

Answer: You can easily use both methods together in the same project. Simply import CSS Modules in your component as described before and add a <style jsx> tag below for any additional local or global Styling JSX needs.

import styles from './Button.module.css';

function Button() {
  return (
    <button className={styles.button}>
      Click me
      <style jsx>{`
        button:hover {
          opacity: 0.7;
        }
      `}</style>
    </button>
  );
}

9. Can I use Tailwind CSS with CSS Modules in Next.js?

Answer: Yes, you can integrate Tailwind CSS with CSS Modules. First, you need to set up Tailwind CSS in your project and configure PostCSS accordingly. After that, you can start using Tailwind classes directly in your CSS Modules.

/* Button.module.css */
.button {
  @apply bg-blue-500 font-bold px-4 py-2 rounded;
}

.button:hover {
  @apply bg-blue-700;
}

To learn more about the setup, refer to the official Tailwind CSS Next.js documentation.

10. How do I configure Styled JSX to work with custom Babel configs or plugins?

Answer: To configure Styled JSX further, e.g., with custom plugins or Babel settings, you must customize your Babel config by placing a .babelrc at your project root. Inside the .babelrc, you can customize the styled-jsx plugin directly.

{
  "presets": ["next/babel"],
  "plugins": [
    [
      "styled-jsx/plugin",
      { "optimizeForSpeed": true }
    ]
  ]
}

In this example, we added a plugin option to optimize Styled JSX for speed. Ensure that this Babel config does not conflict with Next.js default configurations unless necessary.