webpack.dll.js

const path = require('path');
const webpack = require('webpack');

module.exports = env => ({
  entry: {
    vendor: ['react', 'react-dom']
  },
  output: {
    filename: '[name].dll.js',
    library: '[name]',
    path: path.join(__dirname, 'dll')
  },
  plugins: [
    new webpack.DllPlugin({
      context: __dirname,
      name: '[name]',
      path: path.join(__dirname, 'dll', '[name].dll.json')
    })
  ]
});