webpack.config.js

var path = require('path');
var ExtractTextPlugin = require("extract-text-webpack-plugin");
var HtmlWebpackPlugin = require('html-webpack-plugin');
var webpack = require('webpack');

module.exports = {
	entry: './src/index.js',
	mode: 'production',
	output: {
		filename: 'bundle.js',
		path: path.resolve(__dirname, 'lib'),
		library: 'inlineDate',
		libraryTarget: 'umd'
	},
	externals: {
		react: {
			root: 'React',
			commonjs2: 'react',
			commonjs: 'react',
			amd: 'react'
		},
		'react-dom': {
			root: 'ReactDOM',
			commonjs2: 'react-dom',
			commonjs: 'react-dom',
			amd: 'react-dom'
		}
	},
	module: {
		rules: [
			{
				test: /\.js$/,
				use: {
					loader: 'babel-loader',
					options: {
						presets: ['env']
					}
				}
			}
		]
	},
	plugins: [
		new webpack.DefinePlugin({ // <-- key to reducing React's size
			'process.env': {
				'NODE_ENV': JSON.stringify('production')
			}
		}),
		new webpack.optimize.AggressiveMergingPlugin()//Merge chunks
	]
};