Webpack test

index.js

var React = require('react');
var ReactDOM = require('react-dom');
var ReactMarkdown = require('react-markdown');

var input = '# This is a header\n\nAnd this is a paragraph';

ReactDOM.render(
    React.createElement(ReactMarkdown, {source: input}),
    document.getElementById('container')
);

package.json

{
  "name": "wp-test",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "scripts": {
    "build": "webpack"
  },
  "dependencies": {
    "react": "^16.1.0",
    "react-dom": "^16.1.0",
    "react-markdown": "^2.5.0",
    "uglifyjs-webpack-plugin": "^1.0.1",
    "webpack": "^3.8.1"
  }
}

webpack.config.js

var path = require('path')
var webpack = require('webpack')
var UglifyJSPlugin = require('uglifyjs-webpack-plugin');

module.exports = {
  entry: path.join(__dirname, 'index.js'),
  output: {
    filename: 'out.js'
  },
  plugins: [
    new UglifyJSPlugin(),
    new webpack.DefinePlugin({
      'process.env': {
        'NODE_ENV': JSON.stringify('production')
      }
    })
  ]
}