README.md


React integration of JSS

There is a number of benefits when using react-jss instead of JSS directly:

• Lazy evaluation - sheet is created only when component will mount.
• Auto attach/detach - sheet will be rendered to the dom when component is about to mount and will be removed when no element needs it.
• A sheet gets shared between all elements.
• You want to use it with React Hot Loader.

Also you may need this module if you build a big application where leaving all styles in the DOM or compiling all styles at once may have a performance overhead or you are going to hit IE limits.

Usage

You can use it as a higher-order component to inject JSS. It can act both as a simple wrapping function and as a ES7 decorator.

React JSS wraps your React component and injects props.sheet, which is just a regular JSS style sheet, as a prop into your component. This is a common pattern that is used for composition in React instead of mixins, and works equally well with old-style createClass classes, as well as the ES6 classes.

Because JSS class names are namespaced by default, you will need to reach into this.props.sheet.classes to get their real names. For example, if you define a button class in your JSS stylesheet, its real name will be available as props.sheet.classes.button.

By default react-jss comes with jss and presets.

import React from 'react'
import injectSheet from 'react-jss'

const styles = {
  button: {
    backgroundColor: 'yellow'
  },
  label: {
    fontWeight: 'bold'
  }
}

const Button = ({sheet: {classes}, children}) => (
  <button className={classes.button}>
    <span className={classes.label}>
      {children}
    </span>
  </button>
)

export default injectSheet(styles)(Button)

Custom setup.

If you want to specify a jss version and plugins to use, you should create your own jss instance, setup plugins and create a injectSheet function which has your jss version bound.

import {create as createJss} from 'jss'
import {create as createInjectSheet} from 'react-jss'
import vendorPrefixer from 'jss-vendor-prefixer'

const jss = createJss()
jss.use(vendorPrefixer())

export const injectSheet = createInjectSheet(jss)

You can also access the Jss instance being used by default.

import {jss} from 'react-jss'

Using decorators.

You can use ES7 with decorators (using babel-plugin-transform-decorators-legacy).

import React, {Component} from 'react'
import injectSheet from 'react-jss'

const styles = {
  button: {
    backgroundColor: 'yellow'
  },
  label: {
    fontWeight: 'bold'
  }
}

@injectSheet(styles)
export default class Button extends Component {
  render() {
    const {sheet: {classes}, children} = this.props
    return (
      <button className={classes.button}>
        <span className={classes.label}>
          {children}
        </span>
      </button>
    )
  }
}

Using composition for theming

As well as injecting styles directly, react-jss allows you to inject dynamic style sheets based on a ThemeProvider. This provider will pass the theme object via context. The provider can fetch the theme objects from many different sources: using props, a redux store or its own state.

Below I provided an example of how a ThemeProvider would look like, using a theme identifier via props and storing the themes object in its own state. Please note that this example is not part of react-jss.

// ThemeProvider
class ThemeProvider extends React.Component {
  static propTypes = { theme: PropTypes.oneOf([
    'theme1', 'theme2', 'default'
  ]) }
  static defaultProps = { theme: 'default' }
  static childContextTypes = {theme: PropTypes.shape({})}
  constructor(props, context) {
    super(props, context)
    this.state = {
      themes: {
        default: {
          buttonBackgroundColor: 'red',
          labelWeight: 'bold'
        },
        theme1: {
          buttonBackgroundColor: 'white',
          labelWeight: 'normal'
        },
        theme2: {
          buttonBackgroundColor: 'black',
          labelWeight: 'bold'
        }
      }
    }
  }
  getChildContext() {
    return {
      theme: this.state.themes[this.props.theme]
    }
  }
  render() {
    return <div>{children}</div>
  }
}

So if your application renders something like:

<ThemeProvider theme="theme1">
  <form>
    <Button>Save</Button>
  </form>
</ThemeProvider>

It would use the theme1 theme object that define all the style variables of your app. The theme prop can be manipulated by the app the way you prefer, but it needs to define a theme child context for all themed components in order to work.

// Component
import React, {Component} from 'react'
import injectSheet from 'react-jss'

@injectSheet(theme => {
  const { buttonBackgroundColor, labelWeight } = theme;

  return {
    button: {
      backgroundColor: buttonBackgroundColor
    },
    label: {
      fontWeight: labelWeight
    }
  }
})
export default class Button extends Component {
  render() {
    const {sheet: {classes}, children} = this.props
    return (
      <button className={classes.button}>
        <span className={classes.label}>
          {children}
        </span>
      </button>
    )
  }
}

Also, you can define as many theme providers as you can each one defining its own rules. so your components become more reusable by dictating the rules used to style them. Please note that this approach is meant to be used for theming only.

Using classNames helper.

You can use classNames together with JSS same way you do it with global CSS.

import classNames from 'classnames'

const Component = ({sheet: {classes}, children, isActive}) => (
  <div
    className={classNames({
      [classes.normal]: true,
      [classes.active]: isActive
    })}>
    {children}
  </div>
)

Installation.

npm install --save react-jss

License

MIT