3
votes

I'm using the express middlewares instead of webpack-dev-server:

const config = require("../webpack.config.js");

if(process.env.NODE_ENV === 'development') {
    const webpack = require('webpack');
    const webpackDevMiddleware = require('webpack-dev-middleware');
    const webpackHotMiddleware = require('webpack-hot-middleware');
    const compiler = webpack(config);

    app.use(webpackDevMiddleware(compiler, {
        stats: {colors: true},
    }));
    app.use(webpackHotMiddleware(compiler));
}

And I've tried react-hot-loader/patch, react-hot-loader/babel and react-hot-loader/webpack from react-hot-loader@3:

module.exports = {
    context: path.join(__dirname, 'client'),
    entry: [
        'webpack-hot-middleware/client',
        'react-hot-loader/patch',
        './entry.less',
        './entry',
    ],
    output: {
        path: path.join(__dirname, 'public'),
        filename: 'bundle.js',
        publicPath: '/',
    },
    module: {
        rules: [
            {
                test: /\.jsx/,
                use: [
                    {
                        loader: 'babel-loader',
                        options: {
                            plugins: ['transform-react-jsx', 'transform-class-properties', 'react-hot-loader/babel'],
                        },
                    },
                    'react-hot-loader/webpack'
                ],
            },

But none of them seem to work. I just get this error message:

[HMR] The following modules couldn't be hot updated: (Full reload needed) This is usually because the modules which have changed (and their parents) do not know how to hot reload themselves. See http://webpack.github.io/docs/hot-module-replacement-with-webpack.html for more details. logUpdates @ bundle.js:29964 applyCallback @ bundle.js:29932 (anonymous) @ bundle.js:29940 bundle.js:29972
[HMR] - ./client/components/CrawlForm.jsx

What's the trick to making it work?

N.B. CSS hot loading works just fine, so I got that part working.

4

4 Answers

2
votes

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 👍

2
votes

Paraphrasing from Dan Abramov and borrowing some code from realseanp, the full instructions are:

  1. yarn add react-hot-loader@3
  2. Update webpack.config.js:
    1. Add react-hot-loader/patch and webpack-hot-middleware/client to top of your entry
    2. Add react-hot-loader/babel to your babel-loader plugins
    3. Add new HotModuleReplacementPlugin() to your webpack plugins
  3. Add webpack-dev-middleware and webpack-hot-middlware to express:

    // server/entry.jsx
    const express = require('express');
    const path = require('path');
    const cons = require('consolidate');
    const fs = require('fs');
    
    const port = 5469;
    const app = express();
    
    app.disable('x-powered-by');
    app.engine('hbs', cons.handlebars);
    app.set('view engine', 'hbs');
    app.set('views', path.join(__dirname, '../views'));
    
    const wpConfig = require("../webpack.config.js");
    
    if(process.env.NODE_ENV === 'development') {
        const webpack = require('webpack');
        const webpackDevMiddleware = require('webpack-dev-middleware');
        const webpackHotMiddleware = require('webpack-hot-middleware');
        const compiler = webpack(wpConfig);
    
        app.use(webpackDevMiddleware(compiler, {
            stats: {colors: true},
        }));
        app.use(webpackHotMiddleware(compiler));
    }
    
    app.use(require('./routes'));
    
    app.use(express.static(wpConfig.output.path));
    
    app.listen(port, function () {
        console.log(`Listening on http://localhost:${port}`);
    });
    
  4. Add <AppContainer> and react.hot to your client entry point:

    // client/entry.jsx
    import ReactDOM from 'react-dom';
    import App from './components/App';
    import { AppContainer } from 'react-hot-loader';
    
    function render(Root) {
        ReactDOM.render(<AppContainer><Root/></AppContainer>, document.getElementById('react-root'));
    }
    
    render(App);
    
    if(module.hot) {
        module.hot.accept('./components/App', () => {
            render(require('./components/App').default);
        });
    }
    
2
votes

I had some trouble getting the error overlay to render for runtime errors as well as recovering from it. I noticed that webpack-dev-server does a full reload when an error happens.

This can be simulated with the following snippet:

if (module.hot) module.hot.accept('./App', () => {
  try {
    render(App)
  } catch (e) {
    location.reload();
  }
});

My working fork of react-hot-boilerplate is available on Github.

0
votes

I also added every points to my app but it didn't work The problem was at publicPath in my webpack.config.js I had

publicPath: '/client/dist'

then I changed to

publicPath: '/'

And now it works