How to use CSS Modules with webpack in React isomorphic app? - reactjs

Question

I am build an isomorphic app using react, react-router, express and webpack. Now I want to use css modules to import css.
I use import './index.css' in index.jsx, it works fine on client, but doesn't work on server rendering. The error is Error: Cannot find module './index.css'.
components/index.jsx
import React, {Component, PropTypes} from 'react';
import style from './index.css';
class App extends Component {
constructor(props, context) {
super(props, context);
}
render() {
return (
<div id="login">
// ...
</div>
);
}
};
export default App;
server/router/index.js
import url from 'url';
import express from 'express';
import swig from 'swig';
import React from 'react';
import {renderToString} from 'react-dom/server';
import {match, RouterContext} from 'react-router';
import routes from '../../client/routes/routes';
import DataWrapper from '../../client/container/DataWrapper';
import data from '../module/data';
const router = express.Router();
router.get('*', async(req, res) => {
match({
routes,
location: req.url
}, async(error, redirectLocation, props) => {
if (error) {
res.status(500).send(error.message);
} else if (redirectLocation) {
res.status(302).redirect(redirectLocation.pathname + redirectLocation.search);
} else if (props) {
let content = renderToString(
<DataWrapper data={data}><RouterContext {...props}/></DataWrapper>
);
let html = swig.renderFile('views/index.html', {
content,
env: process.env.NODE_ENV
});
res.status(200).send(html);
} else {
res.status(404).send('Not found');
}
});
});
export default router;
webpack.config.dev.js(for webpack-dev-server)
var webpack = require('webpack');
var config = require('./config');
module.exports = {
devtool: 'inline-source-map',
entry: [
'webpack-dev-server/client?http://localhost:' + config.webpackPort,
'webpack/hot/only-dev-server',
'./src/client/entry',
],
output: {
path: __dirname + '/public/js',
filename: 'app.js',
publicPath: 'http://localhost:' + config.webpackPort + '/public/js',
},
plugins: [
new webpack.HotModuleReplacementPlugin(),
new webpack.NoErrorsPlugin(),
new webpack.DefinePlugin({
"process.env": {
NODE_ENV: JSON.stringify('development')
}
})
],
resolve: {
extensions: ['', '.js', '.jsx', '.css']
},
module: {
loaders: [{
test: /\.jsx?$/,
loader: 'react-hot',
exclude: /node_modules/
}, {
test: /\.jsx?$/,
loader: 'babel-loader',
exclude: /node_modules/
}, {
test: /\.css$/,
loader: 'style-loader!css-loader?modules',
exclude: /node_modules/
}, {
test: /\.(png|woff|woff2|svg|ttf|eot)$/,
loader: 'url-loader',
exclude: /node_modules/
}]
}
}

Answer 1

I'd recommend using webpack to compile UI code for both client and server side in that case. Just set target: "node" in webpack config to produce bundle which can executed in Node environment.

Answer 2

That article might help for compiling your server side code with Webpack: http://jlongster.com/Backend-Apps-with-Webpack--Part-I
Especially on how to exclude node_modules with the externals key.
A very bare config might look like:
'use strict';
const path = require('path');
const fs = require('fs');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const rootDir = path.resolve(__dirname, '..');
const distDir = path.join(rootDir, 'dist');
const srcDir = path.join(rootDir, 'src');
const localStyles = new ExtractTextPlugin('local.css', { allChunks: true });
const nodeModules = fs.readdirSync('node_modules')
.filter(dir => !dir.startsWith('.'))
.reduce((acc, prop) => {
acc[prop] = 'commonjs ' + prop;
return acc;
}, {});
const loaders = [
{
test: /\.(js|jsx)$/,
include: srcDir,
exclude: /node_modules/,
loader: 'babel',
query: {
cacheDirectory: true,
},
},
{
test: /\.css$/,
include: srcDir,
loader: localStyles.extract(
'style',
'css?modules&localIdentName=[name]-[local]_[hash:base64:5]'
),
},
{
test: /\.json$/,
loader: 'json',
},
];
module.exports = {
target: 'node',
entry: {
server: ['server/index'],
},
output: {
path: distDir,
filename: '[name].bundle.js',
},
externals: nodeModules,
module: {
loaders,
},
plugins: [
localStyles,
],
};
Another solution (Webpack free) could be to use babel-plugin-css-modules-transform
.