webpack.config.js

const path = require('path');

module.exports = {
  entry: './src/index.js',
  output: {
    path: path.resolve(__dirname, 'lib'),
    filename: 'index.js',
    library: 'ReactContextMenu',
    libraryTarget: 'umd',
    globalObject: 'this',
  },
  mode: 'production',
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        include: [path.resolve(__dirname, 'src')],
        use: {
          loader: 'babel-loader',
          options: {
            presets: [['@babel/preset-env'], ['@babel/preset-react']],
            plugins: [['@babel/plugin-transform-react-jsx']],
          },
        },
      },
      {
        test: /\.(css|less)$/,
        use: [
          { loader: 'style-loader' },
          { loader: 'css-loader' },
          {
            loader: 'postcss-loader',
          },
          { loader: 'less-loader' },
        ],
      },
    ],
  },
  resolve: {
    extensions: ['.js', '.json', '.jsx', '.less', '.css'],
  },
  externals: {
    react: {
      root: 'React',
      commonjs2: 'react',
      commonjs: 'react',
      amd: 'react',
    },
    'react-dom': {
      root: 'ReactDOM',
      commonjs2: 'react-dom',
      commonjs: 'react-dom',
      amd: 'react-dom',
    },
  },
};