Importing CSS files in Isomorphic React Components

Solution 1:

You can't require css in the component that you are rendering on the server. One way to deal with it is to check if it's a browser before requiring css.

if (process.env.BROWSER) {
  require("./style.css");
}

In order to make it possible you should set process.env.BROWSER to false (or delete it) on the server server.js

delete process.env.BROWSER;
...
// other server stuff

and set it to true for the browser. You do it with webpack's DefinePlugin in the config - webpack.config.js

plugins: [
    ...
    new webpack.DefinePlugin({
        "process.env": {
            BROWSER: JSON.stringify(true)
        }
    })
]

You can see this in action in gpbl's Isomorphic500 app.

Solution 2:

If you're building an isomorphic app with ES6 and want to include CSS when rendering on the server (important so basic styles can be sent down to the client in the first HTTP response) check out the @withStyles ES7 decorator used in React Starter Kit.

This little beauty helps ensure users see your content with styles when the page is first rendered. Here's an example isomorphic app I'm building leveraging this technique. Just search the codebase for @withStyles to see how it's used. It goes a little something like this:

import React, { Component, PropTypes } from 'react';
import styles from './ScheduleList.css';
import withStyles from '../../decorators/withStyles';

@withStyles(styles)
class ScheduleList extends Component {

Solution 3:

We had a similar problem with our isomorphic app (and a lot of other problems, you can find details here). As for the problem with CSS import, at first, we were using process.env.BROWSER. Later we've switched to babel-plugin-transform-require-ignore. It works perfectly with babel6.

All you need is to have the following section in your .babelrc

"env": {
   "node": {
     "plugins": [
       [
         "babel-plugin-transform-require-ignore", { "extensions": [".less", ".css"] }
       ]
     ]
   }
}

After that run your app with BABEL_ENV='node'. Like that:

BABEL_ENV='node' node app.js.

Here is an example of how a production config can look like.