What Interviewers Ask Today: Modern CSS Styling Techniques in React (2024)

In today's rapidly evolving frontend landscape, React continues to be a dominant force for building dynamic user interfaces. As of August 2024, understanding the various CSS styling techniques in React is essential for any frontend developer. Interviewers often ask about these methods to assess a candidate's proficiency in writing maintainable and scalable styles in React applications.

In this article, we'll explore the most current CSS styling approaches in React, providing code examples and explanations to help you grasp each technique.

Table of Contents

  1. CSS Modules
  2. Styled Components
  3. Emotion
  4. Tailwind CSS
  5. Sass/SCSS with React
  6. Inline Styles
  7. CSS-in-JS Libraries
  8. Utility-First CSS Frameworks
  9. Conclusion

CSS Modules

What Are CSS Modules?

CSS Modules are a popular way to scope CSS locally to a component in React. They allow you to write traditional CSS, but the class names are automatically made unique at build time.

How to Use CSS Modules

  1. Naming Convention: Rename your CSS files to end with .module.css.
  2. Import the Styles: Import the stylesheet into your component.

Example

Button.module.css

.button {
  background-color: blue;
  color: white;
  padding: 10px;
}

Button.js

import React from 'react'
import styles from './Button.module.css'

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

export default Button

Pros and Cons

  • Pros:
    • Easy to set up.
    • No runtime overhead.
    • Familiar CSS syntax.
  • Cons:
    • No dynamic styling based on props.
    • Can become cumbersome for large applications.

Styled Components

What Are Styled Components?

Styled Components is a popular CSS-in-JS library that utilizes tagged template literals to style components. It allows you to write actual CSS code in your JavaScript.

Installation

npm install styled-components

Example

Button.js

import React from 'react'
import styled from 'styled-components'

const StyledButton = styled.button`
  background-color: ${(props) => (props.primary ? 'blue' : 'gray')};
  color: white;
  padding: 10px;
`

function Button({ primary }) {
  return <StyledButton primary={primary}>Click Me</StyledButton>
}

export default Button

Pros and Cons

  • Pros:
    • Dynamic styling based on props.
    • Automatic vendor prefixing.
    • Elimination of class name bugs.
  • Cons:
    • Adds a runtime overhead.
    • Styling logic mixed with JavaScript logic.

Emotion

What Is Emotion?

Emotion is a performant CSS-in-JS library similar to Styled Components but offers more flexibility and control over styling.

Installation

npm install @emotion/react @emotion/styled

Example

Button.js

import React from 'react'
import styled from '@emotion/styled'

const StyledButton = styled.button`
  background-color: blue;
  color: white;
  padding: 10px;
`

function Button() {
  return <StyledButton>Click Me</StyledButton>
}

export default Button

Pros and Cons

  • Pros:
    • High performance.
    • Rich theming support.
    • Fine-grained control over styles.
  • Cons:
    • Similar drawbacks to other CSS-in-JS solutions.
    • Slightly steeper learning curve.

Tailwind CSS

What Is Tailwind CSS?

Tailwind CSS is a utility-first CSS framework that provides low-level utility classes to build custom designs without leaving your HTML.

Installation

Follow the official installation guide for setting up Tailwind CSS with React.

Example

Button.js

import React from 'react'

function Button() {
  return <button className="bg-blue-500 px-4 py-2 text-white">Click Me</button>
}

export default Button

Pros and Cons

  • Pros:
    • Rapid development.
    • Consistent styling.
    • Highly customizable.
  • Cons:
    • Inline classes can become verbose.
    • Initial setup can be complex.

Sass/SCSS with React

What Is Sass/SCSS?

Sass (Syntactically Awesome Style Sheets) is a CSS preprocessor that adds power and elegance to the basic language.

How to Use Sass with React

  1. Install Sass:

    npm install sass

  2. Rename CSS Files: Change .css files to .scss.

  3. Import Styles: Import the SCSS files into your components.

Example

Button.scss

$button-color: blue;

.button {
  background-color: $button-color;
  color: white;
  padding: 10px;

  &:hover {
    background-color: darken($button-color, 10%);
  }
}

Button.js

import React from 'react'
import './Button.scss'

function Button() {
  return <button className="button">Click Me</button>
}

export default Button

Pros and Cons

  • Pros:
    • Variables, nesting, mixins, and more.
    • Easy to integrate.
  • Cons:
    • Styles are global by default.
    • Potential for class name collisions.

Inline Styles

What Are Inline Styles?

Inline styles involve adding the style attribute directly to your JSX elements.

Example

Button.js

import React from 'react'

function Button() {
  const buttonStyle = {
    backgroundColor: 'blue',
    color: 'white',
    padding: '10px',
  }

  return <button style={buttonStyle}>Click Me</button>
}

export default Button

Pros and Cons

  • Pros:
    • Simple and straightforward.
    • No need to manage separate CSS files.
  • Cons:
    • Lack of pseudo-selectors and media queries.
    • Not ideal for complex styling.

CSS-in-JS Libraries

Beyond Styled Components and Emotion, there are other CSS-in-JS libraries like JSS, Linaria, and stitches.

JSS Example

import React from 'react'
import { createUseStyles } from 'react-jss'

const useStyles = createUseStyles({
  button: {
    backgroundColor: 'blue',
    color: 'white',
    padding: 10,
  },
})

function Button() {
  const classes = useStyles()
  return <button className={classes.button}>Click Me</button>
}

export default Button

Pros and Cons

  • Pros:
    • Scoped styles.
    • Dynamic styling.
  • Cons:
    • Additional library overhead.
    • Similar drawbacks to other CSS-in-JS approaches.

Utility-First CSS Frameworks

Apart from Tailwind CSS, there are other utility-first frameworks like Windi CSS and Tachyons.

Example with Tachyons

import React from 'react'
import 'tachyons/css/tachyons.min.css'

function Button() {
  return <button className="bg-blue white pa3">Click Me</button>
}

export default Button

Pros and Cons

  • Pros:
    • Rapid prototyping.
    • Small bundle size.
  • Cons:
    • Class name clutter.
    • Can be less semantic.

Conclusion

As of August 2024, these are the most prevalent CSS styling techniques in modern React applications. Each method has its own set of advantages and trade-offs, and the choice often depends on the specific needs of your project.

Key Takeaways:

  • CSS Modules: Great for simple projects requiring scoped styles.
  • Styled Components & Emotion: Ideal for dynamic styling with strong community support.
  • Tailwind CSS: Excellent for rapid UI development with utility classes.
  • Sass/SCSS: Adds powerful features to CSS but requires managing global scope.
  • Inline Styles: Best for simple, component-specific styles.
  • CSS-in-JS Libraries: Offer various options for scoped and dynamic styling.

Understanding these approaches will not only prepare you for interview questions but also empower you to make informed decisions in your projects. Always consider factors like scalability, team familiarity, and project requirements when choosing a styling method.