Webpack config for bundling javascript files

webpack.config.js

const path = require('path');
const merge = require('webpack-merge');
const webpack = require('webpack');
// args.getArgs is a custom function that I wrote for yarn
const args = require('./build/utils/args');

// ENV Variables
const client = args.getArg('client') || 'default';
const stubs = args.getArg('stubs');
const PORT = 8080;
const localhost = 'http://127.0.0.1';

const PATHS = {
  app: path.join(__dirname, 'src/index.js')
};

// Common loaders, options, plugins that are for my production and development build
const commonLoaders = {
  module: {
      rules: [
        {
          test: /\.js$/,
          exclude: /(node_modules)/,
          loader: 'babel-loader',
          options: {
            presets: [
              ['es2015', {modules: false}],
              'react'
            ],
            plugins: [ 'react-hot-loader/babel' ]
          }
        }
      ]
    },
    plugins: [ new ProgressBarPlugin() ]
};

// the development or production config that I use in Gulpfile.js
module.exports = function(TARGET) {
  switch(TARGET) {
    case 'build:all':
      return getConfigProd();
    default:
      return getConfigDev();
  }
}

// Production build configuration
function getConfigProd() {
  return merge(commonLoaders, {
      entry: ['babel-polyfill', PATHS.app],
      output: {
        path: path.resolve(__dirname, 'static'),
        publicPath: '/static/',
        filename: "[name].[hash].bundle.js",
      },
      plugins: [
        new webpack.optimize.UglifyJsPlugin({ /*... options ... */ })
      ]
    }
  );
}

// Development build configuration
function getConfigDev() {
  return merge(commonLoaders, {
      entry: [
        'react-hot-loader/patch',
        `webpack-dev-server/client?${localhost}:${PORT}`,
        'webpack/hot/only-dev-server',
        'babel-polyfill',
        PATHS.app
      ],
      watch: true,
      devtool: 'eval',
      output: {
        path: path.resolve(__dirname, 'static'),
        publicPath: '/',
        filename: 'bundle.js'
      }
    },
    require('./build/getDevServerConfig')(PORT, localhost, client)
  );
}