How can I use webpack with express?

What I ended up doing was I used 2 different configurations, 1 for packing the server stuff together using webpack, and 1 for packing all the browser stuff together and also run webpack dev server for hot reloading.

Server webpack config aka webpack.node.config.js now looks like this:

var webpack = require('webpack');
var path = require('path');
var fs = require('fs');
var nodeModules = {};

// note the path.resolve(__dirname, ...) part
// without it, eslint-import-resolver-webpack fails
// since eslint might be invoked with different cwd
fs.readdirSync(path.resolve(__dirname, 'node_modules'))
    .filter(x => ['.bin'].indexOf(x) === -1)
    .forEach(mod => { nodeModules[mod] = `commonjs ${mod}`; });

// es5 style alternative
// fs.readdirSync(path.resolve(__dirname, 'node_modules'))
//     .filter(function(x) {
//         return ['.bin'].indexOf(x) === -1;
//     })
//     .forEach(function(mod) {
//         nodeModules[mod] = 'commonjs ' + mod;    
//     });

module.exports =

{
    // The configuration for the server-side rendering
    name: 'server',
    target: 'node',
    entry: './app/server/serverEntryPrototype.js',
    output: {
        path: './bin/',
        publicPath: 'bin/',
        filename: 'serverEntryPoint.js'
    },
    externals: nodeModules,
    module: {
        loaders: [
            { test: /\.js$/,

                loaders: [
                    // 'imports?document=this',

                    // 'react-hot',
                    'babel-loader'
                    //,'jsx-loader'
                ]
            },
            { test:  /\.json$/, loader: 'json-loader' },
        ]
    },
    plugins: [
    // new webpack.NormalModuleReplacementPlugin("^(react-bootstrap-modal)$", "^(react)$")
    // new webpack.IgnorePlugin(new RegExp("^(react-bootstrap-modal)$"))
    // new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/)
  ]
};

Browser webpack config aka webpack.browser.config.js now looks like this:

var webpack = require('webpack');
var path = require('path');
var buildPath = path.resolve(__dirname, 'assets');
var fs = require('fs');


var commonLoaders = [
    { test: /\.js$/,

        loaders: [
            'react-hot',
            'babel-loader'
            //,'jsx-loader'
        ]
    }
];


module.exports =
{
    // Makes sure errors in console map to the correct file
    // and line number
    name: 'browser',
    devtool: 'eval',
    entry: [
        //'./bin/www.js',
        './app/index.js',
        'webpack/hot/dev-server',
        'webpack-dev-server/client?http://localhost:8081'  // WebpackDevServer host and port
    ],
    output: {
        path: buildPath,
        filename: '[name].js',
        // Everything related to Webpack should go through a build path,