webpack.config.js

const path = require('path');

module.exports = {

  entry: './src/index.js',

  module: {

    rules: [
      {
        test: /\.js$/,
        use: {
          loader: 'babel-loader',
        },
      },
      {
        test: /\.css$/,
        use: [
          { loader: 'style-loader' },
          { loader: 'css-loader' }
        ],
      },
      {
        test: /\.(png|gif|jpg|svg)$/,
        use: {
          loader: 'url-loader',
          options: {
            limit: 50000,
          },
        },
      },
    ],
  },
  resolve: {
    extensions: ['.css', '.js', '.json', '.png', '.gif', '.jpg', '.svg'],
  },
  output: {
    path: path.resolve(__dirname, 'dist/'),
    publicPath: '',
    filename: 'droplite.js',
    libraryTarget: 'umd'
  },
  externals: {
    react: {
      commonjs: "react",
      commonjs2: "react",
      amd: "React",
      root: "React"
    },
    "react-dom": {
      commonjs: "react-dom",
      commonjs2: "react-dom",
      amd: "ReactDOM",
      root: "ReactDOM"
    }
  }
};