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CSS-in-JS Libraries

In this tutorial, we'll explore CSS-in-JS libraries, which allow you to write CSS directly in your JavaScript code. We'll look at the benefits of using these libraries and provide examples using popular libraries like styled-components and Emotion.

What are CSS-in-JS libraries?​

CSS-in-JS libraries allow you to write and manage CSS directly in your JavaScript code. They enable you to apply styles dynamically based on component state, props, or other JavaScript variables.

Benefits of using CSS-in-JS libraries​

  • Scoped styles: Styles are automatically scoped to components, preventing unintended style leaks.
  • Dynamic styling: Easily apply styles based on component state or props.
  • Theming: Manage themes and global styles using JavaScript objects or variables.
  • Enhanced developer experience: Get syntax highlighting, linting, and other benefits provided by JavaScript editors.

Example: styled-components​

Install the styled-components library:

npm install styled-components

Create a styled component and use it in your application:

JavaScript
import styled from 'styled-components';

const Button = styled.button`
  background-color: blue;
  color: white;
  padding: 10px 20px;
  border-radius: 5px;

  &:hover {
    background-color: darkblue;
  }
`;

function App() {
  return (
    <div>
      <Button>Click me!</Button>
    </div>
  );
}

export default App;

Example: Emotion​

Install the @emotion/react library:

npm install @emotion/react

Create a styled component and use it in your application:

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

const buttonStyle = css`
  background-color: blue;
  color: white;
  padding: 10px 20px;
  border-radius: 5px;

  &:hover {
    background-color: darkblue;
  }
`;

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

export default App;

Conclusion​

CSS-in-JS libraries offer a powerful and flexible way to manage CSS directly in your JavaScript code, providing benefits such as scoped styles, dynamic styling, and improved developer experience. By using libraries like styled-components or Emotion, you can create maintainable and dynamic styles for your web applications.