CSS-in-JS: Styled Components vs Emotion

As modern web development evolves, the way we handle CSS has also shifted. Traditional CSS files or embedded styles are being challenged by innovative approaches like CSS-in-JS. Among the notable libraries within this paradigm are Styled Components and Emotion. Both offer unique advantages and capabilities for styling React applications, making them essential tools for developers. In this article, we’ll delve into a detailed comparison of Styled Components and Emotion, helping you determine which one is best suited for your next project.

Understanding CSS-in-JS

CSS-in-JS is a technique where CSS is written inside JavaScript. This development model allows for dynamic styling that can respond to JavaScript logic directly. It promotes encapsulated styles that are scoped to specific components, which helps reduce the risk of style conflicts while enhancing maintainability.

Key Advantages of CSS-in-JS

• Scoped Styles: Since styles are tied to the component, there’s no risk of global scope pollution.
• Dynamic Theming: Easily create themes and switch styles based on application state.
• Enhanced Developer Experience: Utilizing JavaScript allows for powerful features such as conditional styles, functions, and props.

Styled Components

Styled Components is one of the pioneering libraries in the CSS-in-JS space. It leverages tagged template literals to style components and promotes a component-driven development approach.

Features of Styled Components

• Tagged Template Literals: Offers a syntax that is visually appealing and easy to read.
• Automatic Vendor Prefixing: Ensures cross-browser compatibility by adding necessary prefixes automatically.
• Theming Support: Built-in theming features make it easy to manage styles across applications.

Example of Styled Components

Let’s take a look at a basic example of how to use Styled Components in a React application:

import styled from 'styled-components';

const Button = styled.button`
  background-color: #007bff;
  color: white;
  padding: 10px 20px;
  border: none;
  border-radius: 5px;
  cursor: pointer;

  &:hover {
    background-color: #0056b3;
  }
`;

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

In this example, we styled a button component using Styled Components. The CSS is directly tied to the visual representation of the button, making it reusable and maintainable.

Emotion

Emotion is another powerful CSS-in-JS library that aims to provide developers with a highly performant and flexible approach to styling applications. Its dual-API approach (string and object styles) makes it versatile for different coding preferences.

Features of Emotion

• String and Object Styles: Offers options for writing styles using both string literals and JavaScript objects.
• High Performance: Emotion is designed to be fast with a focus on minimizing the size of the CSS generated.
• Wide React Compatibility: Works seamlessly with existing React projects, supporting SSR and more.

Example of Emotion

Here’s how you can create a styled button using Emotion:

/** @jsxImportSource @emotion/react */
import { css } from '@emotion/react';

const buttonStyle = css`
  background-color: #e74c3c;
  color: white;
  padding: 10px 20px;
  border: none;
  border-radius: 5px;
  cursor: pointer;

  &:hover {
    background-color: #c0392b;
  }
`;

function App() {
  return <button css={buttonStyle}> Click Me </button>;
}

In this demonstration, we used Emotion to create a similar button to the one in the Styled Components example. The `css` function enables defining styles even in regular JavaScript code.

Performance Comparison

When comparing performance, both Styled Components and Emotion are designed with optimization in mind. However, there are subtle differences:

• Lazy Loading: Emotion supports lazy loading of styles, which can lead to smaller CSS bundles.
• Style Injection: Styled Components injects styles at runtime, which can impact initial load time in large applications.
• Theming: Both libraries offer theming capabilities, but Emotion’s approach can sometimes be more flexible with dynamic theming.

Community and Ecosystem

Both libraries have robust communities and ecosystems. Styled Components has been around longer and has a larger user base, leading to a broader array of plugins and extensions. However, Emotion is quickly gaining traction due to its flexibility and performance, establishing itself as a strong contender.

Use Cases for Each Library

The choice between Styled Components and Emotion largely depends on specific project demands:

• Styled Components: Ideal for teams looking for easy integration, defined syntax with template literals, and strong community support.
• Emotion: Best for projects that prioritize performance, flexibility in styles, and support for object-based styles.

Conclusion

Both Styled Components and Emotion provide great solutions for styling React applications with CSS-in-JS. Choosing between them often comes down to personal preference, project requirements, and team expertise. Consider experimenting with both libraries to determine which fits your workflow better. Regardless of your choice, embracing CSS-in-JS will lead to a more modular and maintainable styling methodology.

Which library have you chosen for your projects? Share your experiences in the comments below!