webpack.config.js

const path = require('path');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const CompressionPlugin = require('compression-webpack-plugin');
const webpack = require('webpack');

process.env.NODE_ENV = process.env.NODE_ENV || 'development';

if (process.env.NODE_ENV === 'test') {
	require('dotenv').config({ path: '.env.test' });
} else if (process.env.NODE_ENV === 'development') {
	require('dotenv').config({ path: '.env.development' });
}

module.exports = (env) => {
	const isProduction = env === 'production';
	const CSSExtract = new ExtractTextPlugin('styles.css');

	return {
		entry: [ 'babel-polyfill', './src/app.js' ],
		output: {
			path: path.join(__dirname, 'public', 'dist'),
			filename: 'bundle.js'
		},
		module: {
			rules: [
				{
					loader: 'babel-loader',
					test: /\.js$/,
					exclude: /node_modules/
				},
				{
					test: /\.s?css$/,
					use: CSSExtract.extract({
						use: [
							{
								loader: 'css-loader',
								options: {
									sourceMap: true
								}
							},
							{
								loader: 'sass-loader',
								options: {
									sourceMap: true
								}
							}
						]
					})
				}
			]
		},
		plugins: [
			CSSExtract,
			new webpack.DefinePlugin({
				'process.env.FIREBASE_API_KEY': JSON.stringify(process.env.FIREBASE_API_KEY),
				'process.env.FIREBASE_AUTH_DOMAIN': JSON.stringify(process.env.FIREBASE_AUTH_DOMAIN),
				'process.env.FIREBASE_DATABASE_URL': JSON.stringify(process.env.FIREBASE_DATABASE_URL),
				'process.env.FIREBASE_PROJECT_ID': JSON.stringify(process.env.FIREBASE_PROJECT_ID),
				'process.env.FIREBASE_STORAGE_BUCKET': JSON.stringify(process.env.FIREBASE_STORAGE_BUCKET),
				'process.env.FIREBASE_MESSAGING_SENDER_ID': JSON.stringify(process.env.FIREBASE_MESSAGING_SENDER_ID)
			}),
			new CompressionPlugin({
				filename: '[path].gz[query]',
				algorithm: 'gzip',
				test: /\.js(\?.*)?$/i,
				threshold: 10240,
				minRatio: 0.8
			})
		],
		devtool: isProduction ? 'source-map' : 'inline-source-map',
		devServer: {
			contentBase: path.join(__dirname, 'public'),
			publicPath: '/dist/',
			port: 1234,
			open: true,
			openPage: '',
			historyApiFallback: true
		}
	};
};