google-map-react/webpack.config.base.js

const reactExternal = {
  root: 'React',
  commonjs2: 'react',
  commonjs: 'react',
  amd: 'react',
};

const reactDomExternal = {
  root: 'ReactDOM',
  commonjs2: 'react-dom',
  commonjs: 'react-dom',
  amd: 'react-dom',
};

module.exports = {
  output: {
    library: 'GoogleMapReact',
    libraryTarget: 'umd',
  },
  externals: {
    react: reactExternal,
    'react-dom': reactDomExternal,
  },
  module: {
    loaders: [{ test: /\.js$/, exclude: /node_modules/, loader: 'babel' }],
  },
};