webpack.config.js

const webpack = require('webpack')

const env = process.env.NODE_ENV

const config = {
  module: {
    rules: [
      { test: /\.js$/, loaders: ['babel-loader'], exclude: /node_modules/ }
    ]
  },
  mode: env,
  output: {
    library: 'react-handler',
    libraryTarget: 'umd'
  },
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify(env)
    })
  ],
  externals: {
    react: {
      root: 'React',
      commonjs2: 'react',
      commonjs: 'react',
      amd: 'react'
    }
  }
}

module.exports = config