I have a simple HMR setup for reloading typescript files and postcss files. And they work perfectly well and modules reload without a page refresh. But when I change my HTML files, the website doesn't reload on it's own and the HTML content is not being hot-reloaded in.

This is my webpack config file:

const { resolve } = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');

module.exports = {
  entry: resolve(__dirname, 'src/main.ts'),
  output: {
    path: resolve(__dirname, 'dist'),
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.ts$/,
        loader: 'awesome-typescript-loader',
        exclude: /node_modules/,
      },
      {
        test: /\.css$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'style-loader'
          },
          {
            loader: 'css-loader',
            options: {
              importLoaders: 1,
            },
          },
          {
            loader: 'postcss-loader',
          }
        ]
      }
    ]
  },
  devtool: 'source-map',
  mode: 'development',
  plugins: [
    new HtmlWebpackPlugin({
      template: resolve(__dirname, './src/index.html'),
    }),
    new webpack.HotModuleReplacementPlugin(),
    new CleanWebpackPlugin(resolve(__dirname, 'dist'))
  ],
  devServer: {
    contentBase: resolve(__dirname, 'dist'),
    port: 9000,
    hot: true,
    open: true,
    progress: true,
  }
}

I have a simple HMR setup for reloading typescript files and postcss files. And they work perfectly well and modules reload without a page refresh. But when I change my HTML files, the website doesn't reload on it's own and the HTML content is not being hot-reloaded in.

This is my webpack config file:

const { resolve } = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');

module.exports = {
  entry: resolve(__dirname, 'src/main.ts'),
  output: {
    path: resolve(__dirname, 'dist'),
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.ts$/,
        loader: 'awesome-typescript-loader',
        exclude: /node_modules/,
      },
      {
        test: /\.css$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'style-loader'
          },
          {
            loader: 'css-loader',
            options: {
              importLoaders: 1,
            },
          },
          {
            loader: 'postcss-loader',
          }
        ]
      }
    ]
  },
  devtool: 'source-map',
  mode: 'development',
  plugins: [
    new HtmlWebpackPlugin({
      template: resolve(__dirname, './src/index.html'),
    }),
    new webpack.HotModuleReplacementPlugin(),
    new CleanWebpackPlugin(resolve(__dirname, 'dist'))
  ],
  devServer: {
    contentBase: resolve(__dirname, 'dist'),
    port: 9000,
    hot: true,
    open: true,
    progress: true,
  }
}

• javascript
• html
• node.js
• webpack
• config

3 Answers 3

With webpack 5,this setting is work for me:

  devServer: {
    hot:true,
    open:true,
    watchFiles: ['src/**/*']
  },

• webpack-dev-server github issue #3881

Problem is that html-webpack-plugin doesn't react to change and doesn't trigger the hmr. In order to achieve that you could try something like this:

const { resolve } = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');
let devServer; // set below in devserver part

function reloadHtml() {
  this.plugin('pilation',
    thing => thing.plugin('html-webpack-plugin-after-emit', trigger));
  const cache = {};
  function trigger(data, callback) {
    const orig = cache[data.outputName];
    const html = data.html.source();
    if (orig && orig !== html)
      devServer.sockWrite(devServer.sockets, 'content-changed');
    cache[data.outputName] = html;
    callback();
  }
}

module.exports = {
  entry: resolve(__dirname, 'src/main.ts'),
  output: {
    path: resolve(__dirname, 'dist'),
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.ts$/,
        loader: 'awesome-typescript-loader',
        exclude: /node_modules/,
      },
      {
        test: /\.css$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'style-loader'
          },
          {
            loader: 'css-loader',
            options: {
              importLoaders: 1,
            },
          },
          {
            loader: 'postcss-loader',
          }
        ]
      }
    ]
  },
  devtool: 'source-map',
  mode: 'development',
  plugins: [
    reloadHtml,
    new HtmlWebpackPlugin({
      template: resolve(__dirname, './src/index.html'),
    }),
    new webpack.HotModuleReplacementPlugin(),
    new CleanWebpackPlugin(resolve(__dirname, 'dist'))
  ],
  devServer: {
    before(app, server) {
      devServer = server;
    },
    contentBase: resolve(__dirname, 'dist'),
    port: 9000,
    hot: true,
    open: true,
    progress: true,
  }
}

If you get :

DeprecationWarning: Tapable.plugin is deprecated. Use new API on `.hooks` instead

You can change reloadHtml to this:

function reloadHtml() {
  const cache = {}
  const plugin = {name: 'CustomHtmlReloadPlugin'}
  this.hooks.pilation.tap(plugin, pilation => {
    pilation.hooks.htmlWebpackPluginAfterEmit.tap(plugin, data => {
      const orig = cache[data.outputName]
      const html = data.html.source()
      if (orig && orig !== html) {
        devServer.sockWrite(devServer.sockets, 'content-changed')
      }
      cache[data.outputName] = html
    })
  })
}

Not sure if this is the case, but if you only want to extend your current HMR config to do a browser reload when your outer html/view files changed, then you can do it with a few extra lines using chokidar.

Maybe you already have it, because webpack-dev-server is using chokidar internally, but if not found then install it first with npm or yarn:

npm install chokidar --save
yarn add -D chokidar

Then require it in your webpack config:

const chokidar = require('chokidar');

Then in your devServer config:

devServer: {
  before(app, server) {
    chokidar.watch([
      './src/views/**/*.html'
    ]).on('all', function() {
      server.sockWrite(server.sockets, 'content-changed');
    })
  },

Also check the API for more options.

I'm using it with Webpack4. Don't know if it works with earlier versions...

Hope it helps you or others looking for this situation.