webpack.config.js

// Backend config example
// http://jlongster.com/Backend-Apps-with-Webpack--Part-I

var path = require('path');
var webpack = require('webpack');
var fs = require('fs');

var nodeModules = {};
fs.readdirSync('node_modules')
  .filter(function(x) {
    return ['.bin'].indexOf(x) === -1;
  })
  .forEach(function(mod) {
    nodeModules[mod] = 'commonjs ' + mod;
  });

module.exports = {
  target: 'node',
  entry: './src/index.js',
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'bundle.js'
  },
  module: {
    loaders: [
      {
        test: /\.js$/,
        exclude: /(node_modules)/,
        loader: 'babel',
        query: {
          presets: ['es2015']
        }
      },
      {
        test: /\.json$/,
        loader: 'json-loader'
      }
    ]
  },
  externals: nodeModules
};