Webpack dev middleware react hot reload too slow

Adidi picture Adidi · Apr 24, 2016 · Viewed 8.8k times · Source

I have a simple configuration with webpack-dev-middleware and webpack-hot-middleware that uses Hot reload (HMR) with react.

Everything is working fine except that every change i made to the code it takes up 2 3-4 seconds !!! till I see it in the browser. Am I doing something wrong ? it's supposed to be like this ?

My code is rather big and my bundle minified get to 841kb (200kb gzipped) is this the reason ? the more the codebase is bigger the bundle creation in slower?

Express Server:

var webpack = require('webpack');
var webpackConfig = require('./webpack.hot.config');
var compiler = webpack(webpackConfig);

app.use(require("webpack-dev-middleware")(compiler, {
  noInfo: true,
  publicPath: webpackConfig.output.publicPath,
  watchOptions: {
    poll: true
  }
 }));
app.use(require("webpack-hot-middleware")(compiler, {
  log: console.log,
  path: '/__webpack_hmr',
  heartbeat: 10 * 1000
 }));

webpack.hot.config.js

    const path = require('path');
    const webpack = require('webpack');

module.exports = {

context: __dirname,
entry: [
    'webpack-hot-middleware/client?path=/__webpack_hmr&timeout=20000',
    './src/js/index'
],
module: {
    loaders: [{
        test: /\.jsx?$/,
        include: path.join(__dirname, 'src/js'),
        //exclude: /node_modules/,
        loader: 'react-hot!babel'
    },
        {
            // Test expects a RegExp! Note the slashes!
            test: /\.css$/,
            loaders: ['style', 'css'],
            // Include accepts either a path or an array of paths.
            include: path.join(__dirname, 'src/css')
        }
    ]
},
resolve: {
    extensions: ['', '.js', '.jsx']
},
output: {
    path: __dirname + '/public',
    publicPath: '/',
    filename: 'js/app.js'
},
plugins: [
    new webpack.optimize.OccurenceOrderPlugin(),
    new webpack.HotModuleReplacementPlugin(),
    new webpack.NoErrorsPlugin()
]
};

And this is what i get in the console when i changed something in the code:

[HMR] App is up to date.
app.js:73223 [HMR] bundle rebuilding
app.js:73226 [HMR] bundle rebuilt in 335ms
app.js:73289 [HMR] Checking for updates on the server...
app.js:73362 [HMR] Updated modules:
app.js:73364 [HMR]  - ./src/js/components/header.jsx
app.js:73369 [HMR] App is up to date.

Answer

John William Domingo picture John William Domingo · May 3, 2016

Consider switching polling to false in your middleware. I've found that polling can be CPU-intensive.

In you webpack config, you might also want to try adding devtool: false to avoid creating a source map.