How to get react-hot-loader working with webpack 2 and webpackDevMiddleware?

I spent several days before I finally cracked the case. Here's my code that works:

Webpack Config Object

const clientConfig = {
  entry: {
    client: [
      'react-hot-loader/patch',
      'webpack-hot-middleware/client',
      'babel-polyfill',
      './src/client/client.js',
    ],
  },
  output: {
    path: path.resolve(__dirname, './build/public'),
    filename: '[name].js',
    publicPath: '/',
  },
  devtool: 'inline-source-map',
  plugins: [
    new webpack.HotModuleReplacementPlugin(),
    new webpack.NoEmitOnErrorsPlugin(),
    new webpack.LoaderOptionsPlugin({
      debug: true,
    }),
    new CopyWebpackPlugin([
      { from: './src/assets/fonts', to: 'fonts' },
      { from: './src/assets/images', to: 'images' },
    ]),
    new webpack.EnvironmentPlugin(['GOOGLE_MAP_API_KEY']),
  ],
  module: {
    rules: [
      {
        test: /(\.js|\.jsx)$/,
        loader: 'babel-loader',
        exclude: /node_modules/,
        options: {
          presets: [['es2015', { loose: true }], 'react', 'stage-2'],
        },
      },
      {
        test: /\.scss$/,
        use: [
          'style-loader',
          'css-loader',
          'sass-loader',
        ],
      },
    ],
  },
};

Server index.js

I am using both dev middleware and hot middleware same as you. I am also importing AppContainer from react-hot-loader and wrapping my component.

import express from 'express';
import React from 'react';
import routes from 'components/Routes';
import html from './html';
import { renderToString } from 'react-dom/server';
import { match, RouterContext } from 'react-router';
import { Provider } from 'react-redux';
import makeStore from 'store';
import Immutable from 'immutable';
import setupNameless from './setupNameless';
import db from './database';
import { actions } from '../client/constants';
import webpack from 'webpack';
import webpackHotMiddleware from 'webpack-hot-middleware';
import webpackDevMiddleware from 'webpack-dev-middleware';
import { clientConfig as wpConfig } from '../../webpack.config.js';
import { AppContainer } from 'react-hot-loader';
import dotenv from 'dotenv';

dotenv.config();

const compiler = webpack(wpConfig);

db();

const app = express();
app.use(webpackDevMiddleware(compiler, {
  publicPath: wpConfig.output.publicPath,
  // noInfo: true,
  stats: {
    colors: true,
  },
}));
app.use(webpackHotMiddleware(compiler));
app.use(express.static('build/public'));

const { commander: nameless, apiPrefix } = setupNameless(app);

app.use((req, res, next) => {
  // make DB call here to fetch jobs.
  nameless.exec('jobs', actions.GET_JOBS).then((jobs) => {

    const store = makeStore(Immutable.fromJS({
      // filters: {},
      app: {
        apiPrefix,
        search: {
          query: '',
          options: {},
        },
      },
      jobs,
    }));

    match({
      routes,
      location: req.originalUrl,
    }, (error, redirectLocation, renderProps) => {
      if (error) {
        res.status(500).send(error.message);
      } else if (redirectLocation) {
        res.redirect(302, redirectLocation.pathname + redirectLocation.search);
      } else if (renderProps) {
        // You can also check renderProps.components or renderProps.routes for
        // your "not found" component or route respectively, and send a 404 as
        // below, if you're using a catch-all route.
        try {
          res.status(200).send(html(renderToString(
            <AppContainer>
              <Provider store={store}>
                <RouterContext {...renderProps} />
              </Provider>
            </AppContainer>
          ), store.getState()));
        } catch (err) {
          next(err);
        }
      } else {
        res.status(404).send('Not found');
      }
    });
  }, (e) => {
    next(e);
  }).catch(e => {
    next(e);
  });
});

app.use(logErrors);

function logErrors(err, req, res, next) {
  console.error(err.stack);
  next(err);
}

app.listen(process.env.PORT || 3000, () => {
  console.log(`App listening on port ${process.env.PORT || 3000}`);
});

Client.js

This was the magic that made it work. I had to add the if (module.hot) code and also import AppContainer from react-hot-loader. Another important aspect was adding key={Math.random()} to my <Router /> component.

import { match, Router, browserHistory as history } from 'react-router';
import routes from './components/Routes';
import ReactDOM from 'react-dom';
import React from 'react';
import { Provider } from 'react-redux';
import makeStore from './store';
import Immutable from 'immutable';
import createLogger from 'redux-logger';
import createSagaMiddleware from 'redux-saga';
import sagas from './sagas';
import { AppContainer } from 'react-hot-loader';

const logger = createLogger();
const sagaMiddleware = createSagaMiddleware();

const store = makeStore(
    Immutable.fromJS(window.__INITIAL_STATE__),
    logger,
    sagaMiddleware
);

sagaMiddleware.run(sagas);

ReactDOM.render(
  <AppContainer>
    <Provider store={store}>
      <Router history={history} routes={routes} />
    </Provider>
  </AppContainer>,
  document.getElementById('app'));

if (module.hot) {
  module.hot.accept('./components/Routes', () => {
    const nextRoutes = require('./components/Routes').default;
    ReactDOM.render(
      <AppContainer>
        <Provider store={store}>
          <Router key={Math.random()} history={history} routes={nextRoutes} />
        </Provider>
      </AppContainer>,
      document.getElementById('app'));
  });
}

Good luck 👍