webpack.config.js

const path = require('path')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
const UglifyJsPlugin = require('uglifyjs-webpack-plugin')

module.exports = {
  entry: './src/index.js',
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'sage-widget.bundle.js'
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['env', 'react']
          }
        }
      },
      {
        test: /\.css$/,
        use: [
          {
            loader: MiniCssExtractPlugin.loader,
            options: {
              // you can specify a publicPath here
              // by default it use publicPath in webpackOptions.output
              publicPath: '../'
            }
          },
          'css-loader'
        ]
      }
    ]
  },
  resolve: {
    extensions: ['*', '.js', '.jsx']
  },
  node: {
    fs: 'empty',
    net: 'empty',
    tls: 'empty'
  },
  plugins: [
    new UglifyJsPlugin(),
    new MiniCssExtractPlugin({
      filename: '[name].css',
      chunkFilename: '[id].css'
    })
  ]
}