webpack.config.babel.js

import { DefinePlugin, optimize, HotModuleReplacementPlugin } from 'webpack';
import libpath from 'path';
import CleanWebpackPlugin from 'clean-webpack-plugin';

const { UglifyJsPlugin, AggressiveMergingPlugin } = optimize;
const dst = 'docs';
let { env: { NODE_ENV, WATCH } } = process;

if (!NODE_ENV) {
	NODE_ENV = 'production';
}

WATCH = WATCH === 'true';

const isProduction = NODE_ENV === 'production';
const presets = ['react'];
const plugins = [
	new CleanWebpackPlugin([dst], {
		root: __dirname,
		verbose: false,
		dry: false,
		exclude: ['index.html']
	}),
	new DefinePlugin({
		'process.env': {
			NODE_ENV: JSON.stringify(NODE_ENV)
		}
	})
];

if (isProduction) {
	presets.push('es2015');
	plugins.push(
		new UglifyJsPlugin({ compress: { warnings: false }, mangle: true }),
		new AggressiveMergingPlugin()
	);
}

const context = libpath.join(__dirname, 'src');

const config = {
	entry: [
		context
	],
	output: {
		path: libpath.join(__dirname, dst),
		filename: 'index.js'
	},
	module: {
		rules: [
			{
				test: /\.(js|jsx)$/,
				exclude: /node_modules/,
				use: {
					loader: 'babel-loader',
					options: {
						presets,
						plugins: [
							'transform-decorators-legacy',
							['react-css-modules',
								{
									context,
									generateScopedName: '[name]__[local]',
									filetypes: {
										'.scss': {
											syntax: 'postcss-scss'
										}
									}
								}]
						]
					}
				}
			},
			{
				test: /\.scss$/,
				use: [
					'style-loader',
					'css-loader?importLoader=1&modules&localIdentName=[name]__[local]',
					'postcss-loader',
					'sass-loader'
				]
			},
			{
				test: /\.css$/,
				use: [
					'style-loader',
					'css-loader'
				]
			}
		]
	},
	resolve: {
		extensions: ['.js', '.jsx']
	},
	plugins
};

if (WATCH) {
	Object.assign(config, {
		entry: [
			'webpack-dev-server/client?http://0.0.0.0:3000',
			'webpack/hot/only-dev-server',
			libpath.join(__dirname, 'src/')
		],
		devServer: {
			hot: true,
			contentBase: dst,
			port: 3000,
			host: '0.0.0.0',
			inline: true
		}
	});

	config.plugins.push(new HotModuleReplacementPlugin());
}

export default config;