webpack.config.js

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

const SRC_DIR = path.join(__dirname, 'client');
const OUT_DIR = path.join(__dirname, 'public');

module.exports = {
  plugins: [new MiniCssExtractPlugin(
    {
      filename: 'styles.css'
    }
  )],
  entry: path.join(SRC_DIR, 'index.js'),
  output: {
    path: OUT_DIR,
    filename: 'app.js'
  },
  module: {
    rules: [
      {
        test:/\.(js|jsx)$/,
        exclude: /node_modules/,
        use: 'babel-loader'
      },
      {
        test: /\.scss$/,
        use: [
          'style-loader',
          {
            loader: MiniCssExtractPlugin.loader,
            options: {
              esModule: false
            }
          },
          'css-loader',
          'sass-loader'
        ]
      }
    ]
  },

  mode: 'development',
  resolve: {
    extensions: ['.js', '.jsx']
  },
  devtool: 'eval-source-map',
};