React Universal Webpack CSS-loader issue

Question

Does any one know what this Webpack error is caused by:

Module build failed: Unknown word (2:1)

var content = require("!!../../../../../../node_modules/css-loader/index.js?{"importLoaders":1}!./styles.css");

if(typeof content === 'string') content = [[module.id, content, '']];

This occurs when running two instances of webpack, one for the client and one for the server. The client compile fine, however the server prodcuces this error. If I run the config scripts separately there are no issues. I'm assuming there is some kind of conflict with the same CSS file being processed twice? I would like to be able to implement isomorphic-style-loader however even with this loader in replace of style-loader the error occurs. Any help would be greatly appreciated, hit a wall with this one.

start.js

'use strict';

// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = 'development';
process.env.NODE_ENV = 'development';

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on('unhandledRejection', err => {
  throw err;
});

// Ensure environment variables are read.
require('../config/env');

const { exec } = require('child_process');
const fs = require('fs');
const chalk = require('chalk');
const webpack = require('webpack');
const formatWebpackMessages = require('react-dev-utils/formatWebpackMessages');
const WebpackDevServer = require('webpack-dev-server');
const clearConsole = require('react-dev-utils/clearConsole');
const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
const {
  choosePort,
  createCompiler,
  prepareProxy,
  prepareUrls,
} = require('react-dev-utils/WebpackDevServerUtils');
const openBrowser = require('react-dev-utils/openBrowser');
const paths = require('../config/paths');

// const useYarn = fs.existsSync(paths.yarnLockFile);
const isInteractive = process.stdout.isTTY;

// Warn and crash if required files are missing
//if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
if (!checkRequiredFiles([paths.appIndexJs])) {
  process.exit(1);
}

// Tools like Cloud9 rely on this.
const DEFAULT_CLIENT_PORT = parseInt(process.env.PORT, 10) || 3000;
const DEFAULT_SERVER_PORT = parseInt(process.env.PORT, 10) || 5678;
const HOST = process.env.HOST || '0.0.0.0';

// We attempt to use the default port but if it is busy, we offer the user to
// run on a different port. `detect()` Promise resolves to the next free port.
choosePort(HOST, DEFAULT_CLIENT_PORT)
  .then(port => {
    if (port == null) {
      // We have not found a port.
      return;
    }

    const protocol = process.env.HTTPS === 'true' ? 'https' : 'http';
    const appName = require(paths.appPackageJson).name;
    const urls = prepareUrls(protocol, HOST, port);

    // We do this before importing the wepack.config.client.dev otherwise
    // REACT_APP_CLIENT_PORT won't be set at new webpack.DefinePlugin(env.stringified)
    process.env.REACT_APP_CLIENT_PORT = port
    const configWebpackClient = require('../config/webpack.config.client.dev');

    // Create a webpack compiler that is configured with custom messages.
    // we use different compiler
    //const compiler = createCompiler(webpack, configWebpackClient, appName, urls, useYarn);
    const compiler = webpack(configWebpackClient);

    // Load proxy config
    const proxySetting = require(paths.appPackageJson).proxy;
    const proxyConfig = prepareProxy(proxySetting, paths.appPublic);
    const createDevServerConfig = require('../config/webpackDevServer.config');
    // Serve webpack assets generated by the compiler over a web sever.

    const serverConfig = createDevServerConfig(
      proxyConfig,
      urls.lanUrlForConfig
    );

    const clientServer = new WebpackDevServer(compiler, serverConfig);

    // Launch WebpackDevServer.
    clientServer.listen(port, HOST, err => {
      if (err) {
        return console.log(err);
      }
      if (isInteractive) {
        clearConsole();
      }
      console.log(chalk.cyan(`Starting the client on port ${port}...
`));

      choosePort(HOST, DEFAULT_SERVER_PORT)
        .then(portServer => {
          if (portServer == null) {
            // We have not found a port.
            return;
          }

          process.env.REACT_APP_SERVER_PORT = portServer;
          const configWebpackServer = require('../config/webpack.config.server');
          const compiler = webpack(configWebpackServer);
          const urls = prepareUrls(protocol, HOST, portServer);
          let isServerRunning;

          compiler.watch({ // watch options:
            aggregateTimeout: 300,
          }, function(err, stats) {

            const messages = formatWebpackMessages(stats.toJson({}, true));

            if (messages.errors.length) {
              console.log(messages.errors.join('

'));
            }

            if (err)
              console.log('error on webpack server', err);

            if (!isServerRunning) {
              isServerRunning = true
              const nodemon = exec('nodemon --watch build/server build/server/bundle.js build/server/bundle.js')

              // This is to outpout in the terminal the child process
              nodemon.stdout.on('data', function (data) {
                console.log(data.toString());
              });
              nodemon.on('exit', function (code) {
                console.log('nodemon process exited with code ' + code.toString());
              });

              console.log(chalk.yellow(`Starting the server on port ${portServer}...
`));
              // setTimeout(() => { openBrowser(urls.localUrlForBrowser, {app: 'firefoxdeveloperedition'}) }, 1000);
            }
          });
        })
        .catch(err => {
          if (err && err.message) {
            console.log(err.message);
          }
          process.exit(1);
        });
    });
    ['SIGINT', 'SIGTERM'].forEach(function(sig) {
      process.on(sig, function() {
        clientServer.close();
        process.exit();
      })
    });
  })
  .catch(err => {
    if (err && err.message) {
      console.log(err.message);
    }
    process.exit(1);
  });

webpack.config.base.js

'use strict';

const path = require('path');
const webpack = require('webpack');
// const HtmlWebpackPlugin = require('html-webpack-plugin');
// const CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
// const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
// const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
const eslintFormatter = require('react-dev-utils/eslintFormatter');
const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');
const getClientEnvironment = require('./env');
const paths = require('./paths');

const PROD = process.env.NODE_ENV === 'production';

// `publicUrl` is just like `publicPath`, but we will provide it to our app
// as %PUBLIC_URL% in `index.html` and `process.env.PUBLIC_URL` in JavaScript.
// Omit trailing slash as %PUBLIC_PATH%/xyz looks better than %PUBLIC_PATH%xyz.
const publicUrl = '';
// Get environment variables to inject into our app.

const env = getClientEnvironment(publicUrl);

// This is the development configuration.
// It is focused on developer experience and fast rebuilds.
// The production configuration is different and lives in a separate file.
module.exports = {
  bail: PROD,
  // You may want 'eval' instead if you prefer to see the compiled output in DevTools.
  // See the discussion in https://github.com/facebookincubator/create-react-app/issues/343.
  devtool:  PROD ? 'source-map' : 'cheap-module-source-map',
  entry: [],
  output: {},
  resolve: {
    // This allows you to set a fallback for where Webpack should look for modules.
    // We placed these paths second because we want `node_modules` to "win"
    // if there are any conflicts. This matches Node resolution mechanism.
    // https://github.com/facebookincubator/create-react-app/issues/253
    modules: ['node_modules', paths.appNodeModules].concat(
      // It is guaranteed to exist because we tweak it in `env.js`
      process.env.NODE_PATH.split(path.delimiter).filter(Boolean)
    ),
    // These are the reasonable defaults supported by the Node ecosystem.
    // We also include JSX as a common component filename extension to support
    // some tools, although we do not recommend using it, see:
    // https://github.com/facebookincubator/create-react-app/issues/290
    extensions: ['.js', '.json', '.jsx'],
    alias: {

      // Support React Native Web
      // https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
      'react-native': 'react-native-web',
    },
    plugins: [
      // Prevents users from importing files from outside of src/ (or node_modules/).
      // This often causes confusion because we only process files within src/ with babel.
      // To fix this, we prevent you from importing files out of src/ -- if you'd like to,
      // please link the files into your node_modules/ and let module-resolution kick in.
      // Make sure your source files are compiled, as they will not be processed in any way.
      new ModuleScopePlugin(paths.appSrc),
    ],
  },
  module: {
    strictExportPresence: true,
    rules: [
      // TODO: Disable require.ensure as it's not a standard language feature.
      // We are waiting for https://github.com/facebookincubator/create-react-app/issues/2176.
      // { parser: { requireEnsure: false } },

      // First, run the linter.
      // It's important to do this before Babel processes the JS.
      {
        test: /\.(js|jsx)$/,
        enforce: 'pre',
        use: [
          {
            options: {
              formatter: eslintFormatter,

            },
            loader: require.resolve('eslint-loader'),
          },
        ],
        include: paths.appSrc,
      },
      // ** ADDING/UPDATING LOADERS **
      // The "file" loader handles all assets unless explicitly excluded.
      // The `exclude` list *must* be updated with every change to loader extensions.
      // When adding a new loader, you must add its `test`
      // as a new entry in the `exclude` list for "file" loader.

      // "file" loader makes sure those assets get served by WebpackDevServer.
      // When you `import` an asset, you get its (virtual) filename.
      // In production, they would get copied to the `build` folder.
      {
        exclude: [
          /\.html$/,
          /\.(js|jsx)$/,
          /\.css$/,
          /\.json$/,
          /\.bmp$/,
          /\.gif$/,
          /\.jpe?g$/,
          /\.png$/,
        ],
        loader: require.resolve('file-loader'),
        options: {
          name: 'static/media/[name].[hash:8].[ext]',
        },
      },
      // "url" loader works like "file" loader except that it embeds assets
      // smaller than specified limit in bytes as data URLs to avoid requests.
      // A missing `test` is equivalent to a match.
      {
        test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
        loader: require.resolve('url-loader'),
        options: {
          limit: 10000,
          name: 'static/media/[name].[hash:8].[ext]',
        },
      },
      // Process JS with Babel.
      {
        test: /\.(js|jsx)$/,
        include: paths.appSrc,
        loader: require.resolve('babel-loader'),
        options: {

          // This is a feature of `babel-loader` for webpack (not Babel itself).
          // It enables caching results in ./node_modules/.cache/babel-loader/
          // directory for faster rebuilds.
          cacheDirectory: true,
        },
      },
      // ** STOP ** Are you adding a new loader?
      // Remember to add the new extension(s) to the "file" loader exclusion list.
    ],
  },
  plugins: [
    // Makes some environment variables available to the JS code, for example:
    // if (process.env.NODE_ENV === 'development') { ... }. See `./env.js`.
    new webpack.DefinePlugin(env.stringified),
    // Moment.js is an extremely popular library that bundles large locale files
    // by default due to how Webpack interprets its code. This is a practical
    // solution that requires the user to opt into importing specific locales.
    // https://github.com/jmblog/how-to-optimize-momentjs-with-webpack
    // You can remove this if you don't use Moment.js:
    new webpack.IgnorePlugin(/^\./locale$/, /moment$/),
  ],
};

webpack.config.client.dev.js

'use strict';

const autoprefixer = require('autoprefixer');
const path = require('path');
const webpack = require('webpack');
const CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
const paths = require('./paths');
const getClientEnvironment = require('./env');
const WebpackNotifierPlugin = require('webpack-notifier');

const base = require('./webpack.config.base');

const config = Object.assign({}, base)

config.entry = [
    // Include an alternative client for WebpackDevServer. A client's job is to
    // connect to WebpackDevServer by a socket and get notified about changes.
    // When you save a file, the client will either apply hot updates (in case
    // of CSS changes), or refresh the page (in case of JS changes). When you
    // make a syntax error, this client will display a syntax error overlay.
    // Note: instead of the default WebpackDevServer client, we use a custom one
    // to bring better experience for Create React App users. You can replace
    // the line below with these two lines if you prefer the stock client:
    // require.resolve('webpack-dev-server/client') + '?/',
    // require.resolve('webpack/hot/dev-server'),
    require.resolve('react-dev-utils/webpackHotDevClient'),
    // We ship a few polyfills by default:
    require.resolve('./polyfills'),
    // Errors should be considered fatal in development
    require.resolve('react-error-overlay'),
    // Finally, this is your app's code:
    paths.appIndexJs,
    // We include the app code last so that if there is a runtime error during
    // initialization, it doesn't blow up the WebpackDevServer client, and
    // changing JS code would still trigger a refresh.
]

config.output = {
    // Next line is not used in dev but WebpackDevServer crashes without it:
    path: paths.appBuild,
    // Add /* filename */ comments to generated require()s in the output.
    pathinfo: true,
    // This does not produce a real file. It's just the virtual path that is
    // served by WebpackDevServer in development. This is the JS bundle
    // containing code from all our entry points, and the Webpack runtime.
    filename: 'static/js/bundle.js',
    // There are also additional JS chunk files if you use code splitting.
    chunkFilename: 'static/js/[name].chunk.js',
    // This is the URL that app is served from. We use "/" in development.
    publicPath: '/',
    hotUpdateChunkFilename: 'static/[id].[hash].hot-update.js',
    hotUpdateMainFilename: 'static/[hash].hot-update.json',
    // Point sourcemap entries to original disk location
    devtoolModuleFilenameTemplate: info =>
        path.resolve(info.absoluteResourcePath),
}

config.module.rules = config.module.rules.concat([
    // "postcss" loader applies autoprefixer to our CSS.
    // "css" loader resolves paths in CSS and adds assets as dependencies.
    // "style" loader turns CSS into JS modules that inject

React Universal Webpack CSS-loader issue

Answers (1)

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