webpack.config.js

const BrowserSyncPlugin = require('browser-sync-webpack-plugin');
const path = require("path");
const webpack = require("webpack");

// if using any plugins for both dev and production
var plugins = [
  new BrowserSyncPlugin({
    host: 'localhost',
    port: 3000,
    files: ['./index.html'],
    server: { baseDir: ['./'] }
  })];

var devPlugins = []; // if using any plugins for development

var prodPlugins = [
  new webpack.DefinePlugin({
    'process.env': {
      'NODE_ENV': JSON.stringify('production')
    }
  }),
  new webpack.optimize.UglifyJsPlugin({
    compress: {
      warnings: true
    }
  })
];

plugins = plugins.concat(
  process.env.NODE_ENV === 'production' ? prodPlugins : devPlugins
)

module.exports = {
  context: __dirname,
  entry: "./lib/game.js",
  output: {
    path: path.resolve(__dirname, 'lib'),
    filename: "bundle.js"
  },
  plugins: plugins,
  module: {
    loaders: [
      {
        test: [/\.jsx?$/, /\.js?$/],
        exclude: /(node_modules|bower_components)/,
        loader: 'babel-loader',
        query: {
          presets: ['env']
        }
      }
    ]
  },
  devtool: 'source-map',
  resolve: {
    extensions: [".js", ".jsx", "*"]
  }
};