webpack.production.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin')

module.exports = {
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          options: {
            'presets': [
              ['@babel/preset-env', {
                'useBuiltIns': false
              }]
            ],
            'plugins': [
              '@babel/plugin-transform-runtime',
              '@babel/plugin-proposal-class-properties'
            ]
          },
          loader: 'babel-loader'
        }
      },
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader']
      },
      {
        test: /\.module\.s(a|c)ss$/,
        loader: [
          {
            loader: 'style-loader',
            options: {
              attrs: {class: 'BasebotTag'}
            }
          },
          {
            loader: 'css-loader',
            options: {
              modules: true,
              localIdentName: '[name]__[local]___[hash:base64:5]',
              camelCase: true
            }
          },
          {
            loader: 'sass-loader'
          }
        ]
      },
      {
        test: /\.s(a|c)ss$/,
        exclude: /\.module.(s(a|c)ss)$/,
        loader: [
          {
            loader: 'style-loader',
            options: {
              attrs: {class: 'BasebotTag'}
            }
          },
          'css-loader',
          {
            loader: 'sass-loader'
          }
        ]
      }
    ]
  },
  resolve: {
    extensions: ['.js', '.jsx', '.scss']
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: '[name].[hash].css',
      chunkFilename: '[id].[hash].css'
    })
  ]
}