webpack.config.js

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

module.exports = (env) => {
  const isProduction = env === 'production';
  const CSSExtract = new MiniCssExtractPlugin({ filename: 'styles.css' });

  console.log('env', env);
  return {
    entry: './src/app.js',
    output: {
      path: path.resolve(__dirname, 'public'),
      filename: 'bundle.js',
      publicPath: '/'
    },
    module: {
      rules: [
        {
          loader: 'babel-loader',
          test: /\.js$/,
          exclude: /node_modules/
        }, {
          test: /\.s?css$/,
          use: [
            {
              loader: MiniCssExtractPlugin.loader
            },
            {
              loader: 'css-loader',
              options: {
                sourceMap: true
              }
            },
            {
              loader: 'sass-loader',
              options: {
                sourceMap: true
              }
            }
				  ]
      }, {
        test: /\.(jpe?g|png|gif|svg)$/i,
        use: [
          {
            loader: 'file-loader',
            options: {
              outputPath: '/',
              publicPath: '/',
              name: '[name].[ext]',
            },
          }
        ]
      }]
    },
    plugins: [
      CSSExtract
    ],
    devtool: isProduction ? 'source-map' : 'cheap-module-eval-source-map',
    devServer: {
      contentBase: path.join(__dirname, 'public'),
      historyApiFallback: true,
      hot: true
    }
  }
}