gistfile1.txt

// webpack.config.js
module.exports = {
  entry: {
    main: [
      './bootstrap.js'
    ]
  },
  output: {
    path: __dirname,
    filename: '[name].bundle.js'
  },
  module: {
    loaders: [
      {
        test: /\.js?$/,
        exclude: /(node_modules|bootstrap.js)/,
        loader: 'babel'
      }
    ]
  }
};

// bootstrap.js (plain ES5, just requires which get resolved by webpack

require('babel-runtime/core-js/promise').default = require('bluebird');
require('./app')

// app.js (ES6, gets transformed by babel)
export default function request(){
  return new Promise(...)
}