old_contents: /* eslint no-var: 0, no-console: 0 */
  
  import webpack from 'webpack';
  import WebpackDevServer from 'webpack-dev-server';
  
  import webpackConfig from './webpack.client.rails.hot.config';
  
  const hotRailsPort = process.env.HOT_RAILS_PORT || 3500;
  
  const compiler = webpack(webpackConfig);
  
  const devServer = new WebpackDevServer(compiler, {
    contentBase: `http://lvh.me:${hotRailsPort}`,
    publicPath: webpackConfig.output.publicPath,
    hot: true,
    inline: true,
    historyApiFallback: true,
    quiet: false,
    noInfo: false,
    lazy: false,
    stats: {
      colors: true,
      hash: false,
      version: false,
      chunks: false,
      children: false,
    },
  });
  
  devServer.listen(3500, 'localhost', err => {
    if (err) console.error(err);
    console.log(
      `=> 🔥  Webpack development server is running on port ${hotRailsPort}`
    );
  });
  
new_contents: /* eslint no-var: 0, no-console: 0 */
  
  import webpack from 'webpack';
  import WebpackDevServer from 'webpack-dev-server';
  
  import webpackConfig from './webpack.client.rails.hot.config';
  
  const hotRailsPort = process.env.HOT_RAILS_PORT || 3500;
  
  const compiler = webpack(webpackConfig);
  
  const devServer = new WebpackDevServer(compiler, {
    contentBase: `http://lvh.me:${hotRailsPort}`,
    publicPath: webpackConfig.output.publicPath,
    hot: true,
    inline: true,
    historyApiFallback: true,
    quiet: false,
    noInfo: false,
    lazy: false,
    stats: {
      colors: true,
      hash: false,
      version: false,
      chunks: false,
      children: false,
    },
  });
  
  devServer.listen(hotRailsPort, 'localhost', err => {
    if (err) console.error(err);
    console.log(
      `=> 🔥  Webpack development server is running on port ${hotRailsPort}`
    );
  });
  
subject: Update dev server command to use rails port variable (#326)