HTML Webpack Plugin

This is a webpack plugin that simplifies creation of HTML files to serve your webpack bundles. This is especially useful for webpack bundles that include a hash in the filename which changes every compilation. You can either let the plugin generate an HTML file for you, supply your own template using lodash templates or use your own loader.

Maintainer: Jan Nicklas @jantimon and Thomas Sileghem @mastilver

Installation

Install the plugin with npm:

$ npm install html-webpack-plugin --save-dev

Third party addons:

The html-webpack-plugin provides hooks to extend it to your needs. There are already some really powerful plugins which can be integrated with zero configuration:

webpack-subresource-integrity for enhanced asset security
appcache-webpack-plugin for iOS and Android offline usage
favicons-webpack-plugin which generates favicons and icons for iOS, Android and desktop browsers
html-webpack-harddisk-plugin can be used to always write to disk the html file, useful when webpack-dev-server / HMR are being used
html-webpack-inline-source-plugin to inline your assets in the resulting HTML file
html-webpack-exclude-assets-plugin for excluding assets using regular expressions
html-webpack-include-assets-plugin for including lists of js or css file paths (such as those copied by the copy-webpack-plugin).
script-ext-html-webpack-plugin to add async, defer or module attributes to your<script> elements, or even in-line them
style-ext-html-webpack-plugin to convert your <link>s to external stylesheets into <style> elements containing internal CSS
resource-hints-webpack-plugin to add resource hints for faster initial page loads using <link rel='preload'> and <link rel='prefetch'>
preload-webpack-plugin for automatically wiring up asynchronous (and other types) of JavaScript chunks using <link rel='preload'> helping with lazy-loading
link-media-html-webpack-plugin allows for injected stylesheet <link /> tags to have their media attribute set automatically; useful for providing specific desktop/mobile/print etc. stylesheets that the browser will conditionally download
inline-chunk-manifest-html-webpack-plugin for inlining webpack's chunk manifest. Default extracts manifest and inlines in <head>.

Basic Usage

The plugin will generate an HTML5 file for you that includes all your webpack bundles in the body using script tags. Just add the plugin to your webpack config as follows:

var HtmlWebpackPlugin = require('html-webpack-plugin');
var webpackConfig = {
  entry: 'index.js',
  output: {
    path: __dirname + '/dist',
    filename: 'index_bundle.js'
  },
  plugins: [new HtmlWebpackPlugin()]
};

This will generate a file dist/index.html containing the following:

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Webpack App</title>
  </head>
  <body>
    <script src="index_bundle.js"></script> 
  </body>
</html>

If you have multiple webpack entry points, they will all be included with script tags in the generated HTML.

If you have any CSS assets in webpack's output (for example, CSS extracted with the ExtractTextPlugin) then these will be included with <link> tags in the HTML head.

Configuration

You can pass a hash of configuration options to HtmlWebpackPlugin. Allowed values are as follows:

title: The title to use for the generated HTML document.
filename: The file to write the HTML to. Defaults to index.html. You can specify a subdirectory here too (eg: assets/admin.html).
template: Webpack require path to the template. Please see the docs for details.
inject: true | 'head' | 'body' | false Inject all assets into the given template or templateContent - When passing true or 'body' all javascript resources will be placed at the bottom of the body element. 'head' will place the scripts in the head element.
favicon: Adds the given favicon path to the output html.
minify: {...} | false Pass html-minifier's options as object to minify the output.
hash: true | false if true then append a unique webpack compilation hash to all included scripts and CSS files. This is useful for cache busting.
cache: true | false if true (default) try to emit the file only if it was changed.
showErrors: true | false if true (default) errors details will be written into the HTML page.
chunks: Allows you to add only some chunks (e.g. only the unit-test chunk)
chunksSortMode: Allows to control how chunks should be sorted before they are included to the html. Allowed values: 'none' | 'auto' | 'dependency' |'manual' | {function} - default: 'auto'
excludeChunks: Allows you to skip some chunks (e.g. don't add the unit-test chunk)
xhtml: true | false If true render the link tags as self-closing, XHTML compliant. Default is false

Here's an example webpack config illustrating how to use these options:

{
  entry: 'index.js',
  output: {
    path: __dirname + '/dist',
    filename: 'index_bundle.js'
  },
  plugins: [
    new HtmlWebpackPlugin({
      title: 'My App',
      filename: 'assets/admin.html'
    })
  ]
}

FAQ

Generating Multiple HTML Files

To generate more than one HTML file, declare the plugin more than once in your plugins array:

{
  entry: 'index.js',
  output: {
    path: __dirname + '/dist',
    filename: 'index_bundle.js'
  },
  plugins: [
    new HtmlWebpackPlugin(), // Generates default index.html
    new HtmlWebpackPlugin({  // Also generate a test.html
      filename: 'test.html',
      template: 'src/assets/test.html'
    })
  ]
}

Writing Your Own Templates

If the default generated HTML doesn't meet your needs you can supply your own template. The easiest way is to use the template option and pass a custom HTML file. The html-webpack-plugin will automatically inject all necessary CSS, JS, manifest and favicon files into the markup.

plugins: [
  new HtmlWebpackPlugin({
    title: 'Custom template',
    template: 'my-index.ejs', // Load a custom template (ejs by default see the FAQ for details)
  })
]

my-index.ejs:

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8"/>
    <title><%= htmlWebpackPlugin.options.title %></title>
  </head>
  <body>
  </body>
</html>

If you already have a template loader, you can use it to parse the template. Please note that this will also happen if you specifiy the html-loader and use .html file as template.

module: {
  loaders: [
    { test: /\.hbs$/, loader: "handlebars" }
  ]
},
plugins: [
  new HtmlWebpackPlugin({
    title: 'Custom template using Handlebars',
    template: 'my-index.hbs'
  })
]

You can use the lodash syntax out of the box. If the inject feature doesn't fit your needs and you want full control over the asset placement use the default template of the html-webpack-template project as a starting point for writing your own.

The following variables are available in the template:

htmlWebpackPlugin: data specific to this plugin

htmlWebpackPlugin.files: a massaged representation of the assetsByChunkName attribute of webpack's stats object. It contains a mapping from entry point name to the bundle filename, eg:

"htmlWebpackPlugin": {
  "files": {
    "css": [ "main.css" ],
    "js": [ "assets/head_bundle.js", "assets/main_bundle.js"],
    "chunks": {
      "head": {
        "entry": "assets/head_bundle.js",
        "css": [ "main.css" ]
      },
      "main": {
        "entry": "assets/main_bundle.js",
        "css": []
      },
    }
  }
}

If you've set a publicPath in your webpack config this will be reflected correctly in this assets hash.

htmlWebpackPlugin.options: the options hash that was passed to the plugin. In addition to the options actually used by this plugin, you can use this hash to pass arbitrary data through to your template.

webpack: the webpack stats object. Note that this is the stats object as it was at the time the HTML template was emitted and as such may not have the full set of stats that are available after the webpack run is complete.
webpackConfig: the webpack configuration that was used for this compilation. This can be used, for example, to get the publicPath (webpackConfig.output.publicPath).

Filtering chunks

To include only certain chunks you can limit the chunks being used:

plugins: [
  new HtmlWebpackPlugin({
    chunks: ['app']
  })
]

It is also possible to exclude certain chunks by setting the excludeChunks option:

plugins: [
  new HtmlWebpackPlugin({
    excludeChunks: ['dev-helper']
  })
]

Events

To allow other plugins to alter the HTML this plugin executes the following events:

Async:

html-webpack-plugin-before-html-generation
html-webpack-plugin-before-html-processing
html-webpack-plugin-alter-asset-tags
html-webpack-plugin-after-html-processing
html-webpack-plugin-after-emit

Sync:

html-webpack-plugin-alter-chunks

Example implementation: html-webpack-harddisk-plugin

Usage:

// MyPlugin.js
 
function MyPlugin(options) {
  // Configure your plugin with options...
}
 
MyPlugin.prototype.apply = function(compiler) {
  // ...
  compiler.plugin('compilation', function(compilation) {
    console.log('The compiler is starting a new compilation...');
 
    compilation.plugin('html-webpack-plugin-before-html-processing', function(htmlPluginData, callback) {
      htmlPluginData.html += 'The magic footer';
      callback(null, htmlPluginData);
    });
  });
 
};
 
module.exports = MyPlugin;

Then in webpack.config.js

plugins: [
  new MyPlugin({options: ''})
]

Note that the callback must be passed the htmlPluginData in order to pass this onto any other plugins listening on the same html-webpack-plugin-before-html-processing event.

Contribution

You're free to contribute to this project by submitting issues and/or pull requests. This project is test-driven, so keep in mind that every change and new feature should be covered by tests. This project uses the semistandard code style.

Before running the tests, make sure to execute yarn link and yarn link html-webpack-plugin (or the npm variant of this).

License

This project is licensed under MIT.