Radium

npm install radium

Radium is a set of tools to manage inline styles on React elements. It gives you powerful styling capabilities without CSS.

Inspired by React: CSS in JS by vjeux.

Overview

Eliminating CSS in favor of inline styles that are computed on the fly is a powerful approach, providing a number of benefits over traditional CSS:

Scoped styles without selectors
Avoids specificity conflicts
Source order independence
Dead code elimination
Highly expressive

Despite that, there are some common CSS features and techniques that inline styles don't easily accommodate: media queries, browser states (:hover, :focus, :active) and modifiers (no more .btn-primary!). Radium offers a standard interface and abstractions for dealing with these problems.

When we say expressive, we mean it: math, concatenation, regex, conditionals, functions–JavaScript is at your disposal. Modern web applications demand that the display changes when data changes, and Radium is here to help.

For a short technical explanation, see How does Radium work?.

Convinced about CSS in JS with React, but not Radium? Check out our comprehensive comparison of 14+ alternatives.

Features

Conceptually simple extension of normal inline styles
Browser state styles to support :hover, :focus, and :active
Media queries
Automatic vendor prefixing
Keyframes animation helper
ES6 class and createClass support

Docs

Usage

Start by adding the @Radium decorator to your component class. Alternatively, wrap Radium() around your component, like module.exports = Radium(Component), or Component = Radium(Component), which works with classes and createClass. Then, write a style object as you normally would with inline styles, and add in styles for interactive states and media queries. Pass the style object to your component via style={...} and let Radium do the rest!

<Button kind="primary">Radium Button</Button>

var Radium = require('radium');
var React = require('react');
var color = require('color');

@Radium
class Button extends React.Component {
  static propTypes = {
    kind: React.PropTypes.oneOf(['primary', 'warning']).isRequired
  };

  render() {
    // Radium extends the style attribute to accept an array. It will merge
    // the styles in order. We use this feature here to apply the primary
    // or warning styles depending on the value of the `kind` prop. Since its
    // all just JavaScript, you can use whatever logic you want to decide which
    // styles are applied (props, state, context, etc).
    return (
      <button
        style={[
          styles.base,
          styles[this.props.kind]
        ]}>
        {this.props.children}
      </button>
    );
  }
}

// You can create your style objects dynamically or share them for
// every instance of the component.
var styles = {
  base: {
    color: '#fff',

    // Adding interactive state couldn't be easier! Add a special key to your
    // style object (:hover, :focus, :active, or @media) with the additional rules.
    ':hover': {
      background: color('#0074d9').lighten(0.2).hexString()
    }
  },

  primary: {
    background: '#0074D9'
  },

  warning: {
    background: '#FF4136'
  }
};

Examples

To see local examples in action, do this:

npm install
npm run examples

How does Radium work?

Following is a short technical explanation of Radium's inner workings:

Wrap the render function
Recurse into the result of the original render
For each element:
- Add handlers to props if interactive styles are specified, e.g. onMouseEnter for :hover, wrapping existing handlers if necessary
- If any of the handlers are triggered, e.g. by hovering, Radium calls setState to update a Radium-specific field on the components state object
- On re-render, resolve any interactive styles that apply, e.g. :hover, by looking up the element's key or ref in the Radium-specific state

Contributing

Please see CONTRIBUTING

dariocravero/radium