README

React CSJS

React Higher Order Component for CSJS. Automatically mounts/unmounts styles, works with React Hot Loader. Inspired by the JSS-equivalent, react-jss.

Auto-mount/unmounting of styles

The benefit of using react-csjs instead of using CSJS directly is auto-mount/unmount so that only the styles relevant to which components are currently rendered into the DOM will be mounted; and then once those components are removed/unmounted, so will their styles.

Installation

You'll need to install both csjs and react-csjs like so:

npm install --save csjs react-csjs

Usage

tagged `@decorator` syntax

You can use react-csjs as a higher order component via the decorators syntax (which you'll need something like babel-plugin-transform-decorators-legacy for it to work).

Simply pass the CSS as a string literal. If CSJS plugins like babel-plugin-csjs-postcss are used, they will apply their transforms as usual as long as the default export is named "csjs".

import React from 'react';
import csjs from 'react-csjs';

@csjs`
.button {
  background-color: purple
}
.label {
  color: blue
}`
export default class Button extends React.Component {
  render() {
    return (
      <div className={this.props.classes.button}>
        <span className={this.props.classes.label}>
          {this.props.children}
        </span>
      </div>
    )
  }
}

`@decorator` syntax

You can also use react-csjs as a higher order component in combination with CSJS via the decorators syntax. The decorator can be exported under any name, in this case "withStyles."

import React from 'react';
import csjs from 'csjs';
import withStyles from 'react-csjs';

const styles = csjs`
.button {
  background-color: purple
}
.label {
  color: blue
}`;

@withStyles(styles)
export default class Button extends React.Component {
  render() {
    return (
      <div className={this.props.classes.button}>
        <span className={this.props.classes.label}>
          {this.props.children}
        </span>
      </div>
    )
  }
}

Default export wrapper

Or you can wrap your default export if you'd prefer not to use the decorator syntax, or you're applying to a stateless functional component, like so:

import React from 'react';
import csjs from 'csjs';
import withStyles from 'react-csjs';

const styles = csjs`
.button {
  background-color: purple
}
.label {
  color: blue
}`;

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

export default withStyles(styles)(Button);

The `classes` property

react-csjs adds its own classes prop to the higher order component which contains the same CSJS object that was passed in through withStyles. You are welcome to use classes or the original styles object if it is still in scope, but in some circumstances the classes prop may be your only option.

Popular linting rules such as react/prop-types from eslint-plugin-react will complain that the classes prop is missing from props validation. There are several ways to address this:

Add the classes prop to your component's propTypes:

Button.propTypes = {
  classes: React.PropTypes.objectOf(React.PropTypes.object).isRequired,
};

Tweak the lint rule to ignore the classes prop:

"prop-types": [2, { "ignore": ["classes"] }]

Server-side Rendering

react-csjs fully supports isomorphic/universal apps out of the box. You simply call the provided getStyle() method to grab all of your app's styles after rendering your app to string, like so:

/* server.js */

import React from 'react';
import ReactDOM from 'react-dom/server';
import express from 'express';
import App from './App';
import { getStyle } from 'react-csjs';

const server = express();

// Render the app
const renderedApp = ReactDOM.renderToString(<App />);
// Gather the generated styles
const renderedStyles = getStyle();

server.get('/', (req, res) => {
  res.send(`
    <html>
      <head>
        <style id="ssr-styles">${renderedStyles}</style>
      </head>
      <body>
        <div id="root">${renderedApp}</div>
        <script src="/bundle.main.js"></script>
      </body>
    </html>
  `);
});

server.listen(3000);

You can then remove the SSR styles after rendering on the client.

NOTE: Although this step is not strictly necessary, without removing the SSR styles, you'll effectively have 2 declarations for every style definition: one for the server rendered and one for the auto-mounted styles on the client.

/* client.js */

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import { removeStyle } from 'react-csjs';

const root = document.getElementById('root');
const ssrStyles = document.getElementById('ssr-styles');

// Render the app client-side
ReactDOM.render(<App />, root);

// Can now safely remove the SSR styles since from here on,
// styles will be auto-mounted by react-csjs
removeStyle(ssrStyles);

Example App

You can see a fully working example of an isomorphic/universal React app using react-csjs in the /example directory.

Usage no npm install needed!