tl;dr:

If you use HtmlWebpackPlugin and ExtractTextPlugin in your Webpack builds to create HTML <link>s to external stylesheet files, add this plugin to convert the links to <style> elements containing internal (sometimes incorrectly called 'in-line') CSS.

This is an extension plugin for the Webpack plugin HtmlWebpackPlugin - a plugin that simplifies the creation of HTML files to serve your webpack bundles.

The raw HtmlWebpackPlugin can bundle CSS assets as <link> elements if used in conjunction with ExtractTextPlugin. This extension plugin builds on this by moving the CSS content generated by ExtractTextPlugin from an external CSS file to an internal <style> element.

As of v3.2.x you can specify where in the html this <style> element is inserted.

As of v3.3.x, you can specify minification options for the inlined styles.

Note: this is for internalizing <style>'s only - if you wish to inline <scripts>'s please take a look at:

• inlining feature of sister plugin script-ext-html-webpack-plugin;
• the HtmlWebpackPlugin inline example based on jade templates.

Installation

You can be running webpack v1.x or v2.x on node v4 or higher.

Install the plugin with npm:

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

Note: you may see the following warning:

npm WARN html-webpack-plugin@XXX requires a peer of webpack@* but none was installed.

This is fine - for testing, we dynamically download multiple version of webpack (via the dynavers module).

Important Upgrade Note

Your v2.x configuration will no longer work

Version 3.x is a complete rewrite of the plugin with a completely new configuration and using a completely new mechanism.

The plugin now piggy-backs on ExtractTextPlugin's functionality so works in any use case that ExtractTextPlugin works. This has the convenient effect of fixing all raised issues with v2.x.

However ExtractTextPlugin does not support HMR (Hot Module Replacement). See the 'Use Case: Hot Module Replacement' below for more.

Basic Usage

Use Case: Internalize all your CSS

Add the plugin to your webpack config.

The order is important - the plugin must come after HtmlWebpackPlugin and ExtractTextWebpackPlugin:

module: {
  loaders: [
    { test: /\.css$/, loader: ExtractTextPlugin.extract(...)}
  ]
}
plugins: [
  new HtmlWebpackPlugin({...}),
  new ExtractTextWebpackPlugin('styles.css'),
  new StyleExtHtmlWebpackPlugin()  << add the plugin
]

That's it.

Note that for this simple configuration, HtmlWebpackPlugin's inject option must not be false. However, this constraint does not apply if you specify the position - see 'Use Case: Specifying Position of Style Element' below

Use Case: Internalize critical CSS only

Add the plugin and use more than one loader for your CSS:

module: {
  loaders: [
    { test: /critical.css/, loader: ExtractTextPlugin.extract(...)},
    { test: /other.css/, loader: 'style-loader!css-loader'},  << add separate loader
  ]
}
plugins: [
  new HtmlWebpackPlugin({...}),
  new ExtractTextWebpackPlugin('styles.css'),
  new StyleExtHtmlWebpackPlugin()
]

Use Case: Internalize critical CSS with all other CSS in an external file

Use two instances of ExtractTextPlugin and tell StyleExtWebpackPlugin which one to target by giving it the name of the output file:

const internalCSS = new ExtractTextPlugin('internal.css');
const externalCSS = new ExtractTextPlugin('styles.css');
return {
  ...
  module: {
    loaders: [
      { test: /critical.css/, loader: internalCSS.extract(...)},
      { test: /other.css/, loader: externalCSS.extract(...)},
    ]
  }
  plugins: [
    new HtmlWebpackPlugin({...}),
    internalCSS,
    externalCSS,
    new StyleExtHtmlWebpackPlugin('internal.css') << tell the plugin which to target
  ]
}

Use Case: Specifying Position of Style Element

In the above cases, the positioning of the <style element is controlled by the inject option specified by html-webpack-plugin. For more control, you can use an extended, hash version of the configuration. This can have the following properties:

• enabled: [true|false] - for switching the plugin on and off (default: true);
• file: the css filename - previously, the single String argument (default: undefined - uses the first css file found in the compilation);
• chunks: which chunks the plugin scans for the css file - see the next Use Case: Multiple HTML files for usage (default: undefined - scans all chunks);
• position: [head-top|head-bottom|body-top|body-bottom|plugin] - all (hopefully) self-explanatory except plugin, which means defer to html-webpack-plugin's inject option (default: plugin);
• minify: see next section
• cssRegExp: A regular expression that indicates the css filename (default: /.css$/);

So to put the CSS at the bottom of the <head> element:

module: {
  loaders: [
    { test: /\.css$/, loader: ExtractTextPlugin.extract(...)}
  ]
}
plugins: [
  new HtmlWebpackPlugin({...}),
  new ExtractTextWebpackPlugin('styles.css'),
  new StyleExtHtmlWebpackPlugin({
    position: 'head-bottom'
  })
]

Use Case: Minification/Optimisation

The inlined CSS can be minified/optimised using the extended, hash version of the configuration. Use the minify property with one of the following values:

• false: the default, does not minify;
• true: minifies with default options;
• a hash of the minification options. Minification is carried out by the clean-css optimizer (thanks, @jakubpawlowicz!). See its documentation for the available options.

Default minification:

plugins: [
  ...
  new StyleExtHtmlWebpackPlugin({
    minify: true
  })
]

Custom minification:

plugins: [
  ...
  new StyleExtHtmlWebpackPlugin({
    minify: {
      level: {
        1: {
          all: false,
          tidySelectors: true
        }
      }
    }
  })
]

Use Case: Sass/PostCSS Processing etc.

All as per ExtractTextPlugin.

Use Case: Multiple HTML files

html-webpack-plugin can generate multiple html files if you use multiple instances of the plugin. If you want each html page to be based on different assets (e.g a set of pages) you do this by focussing each html-webpack-plugin instance on a particular entry point via its chunks configuration option.

style-ext-html-webpack-plugin supports this approach by offering the same chunks option. As you also need an instance of extract-text-webpack-plugin, the configuration is quite unwieldy:

...
const page1Extract = new ExtractTextPlugin('page1.css');
const page2Extract = new ExtractTextPlugin('page2.css');
const webpackConfig = {
  ...
  entry: {
    entry1: 'page-1-path/script.js',
    entry2: 'page-2-path/script.js'
  },
  output.filename = '[name].js',
  module.loaders: [
    {
      test: /\.css$/,
      loader: page1Extract.extract('style-loader', 'css-loader'),
      include: [
        'page-1-path'
      ]
    },
    {
      test: /\.css$/,
      loader: page2Extract.extract('style-loader', 'css-loader'),
      include: [
        'page-2-path'
      ]
    }
  ],
  plugins: [
    new HtmlWebpackPlugin({
      chunks: ['entry1'],
      filename: 'page1.html'
    }),
    new HtmlWebpackPlugin({
      chunks: ['entry2'],
      filename: 'page2.html'
    }),
    page1Extract,
    page2Extract,
    new StyleExtHtmlWebpackPlugin({
      chunks: ['entry1']
    }),
    new StyleExtHtmlWebpackPlugin({
      chunks: ['entry2']
    })
  ],
  ...
}
return webpackConfig;

Phew! A loop is recommended instead.

Use Case: Hot Module Replacement

As discussed earlier, ExtractTextPlugin does not support HMR. If you really need this for your CSS you have two options:

1. revert to/stick with v2.x of the plugin;
2. only internalize the CSS on production builds.

The former option is viable if v2.x supports your requirements but that version is no longer maintained hence the second approach is recommended.

For this, use a conditional in your webpack.config to:

• select between ExtractTextPlugin or a loader that supports HMR such as the style-loader;
• either remove the StyleExtPlugin or disable it by passing false to its constructor:

const DEBUG = (process.env.NODE_ENV !== 'production');
return {
  ...
  module: {
    loaders: [
      {
        test: /\.css$/,
        loader: DEBUG ? 'style-loader|css-loader' : ExtractTextPlugin.extract({...})
      }
    ]
  },
  plugins: [
    new HtmlWebpackPlugin({...}),
    new ExtractTextPlugin('styles.css'),
    new StyleExtHtmlWebpackPlugin(!DEBUG)
  ]
}

Debugging

If you have any problems, check the HTML file outputted by HtmlWebpackPlugin. As long as it has the showErrors configuration option set (the default), any errors from StyleExt will be displayed there.

Your next step is to simply remove the StyleExtPlugin and check that ExtractTextPlugin works by itself.

If it does and reintroducing StyleExtPlugin still has problems, please raise an issue giving your configuration and, please, DEBUG output. The DEBUG output is generated by the debug tool which is enabled by setting the DEBUG=StyleExt environmental variable:

DEBUG=StyleExt webpack

The output of a working configuration will look something like:

StyleExt constructor: enabled=true, filename=undefined
StyleExt html-webpack-plugin-alter-asset-tags: CSS file in compilation: 'styles.css'
StyleExt html-webpack-plugin-alter-asset-tags: CSS in compilation: @import url(https://fonts.googleapis.com/css?family=Indie+Flower);...
StyleExt html-webpack-plugin-alter-asset-tags: link element found for style path 'styles.css'
StyleExt html-webpack-plugin-alter-asset-tags: completed)

Change History

• 3.4.1 - updating dependencies / typos on README
• 3.4.0 - add explicit css file matching (thanks @mastilver for the complete PR), updated dependecies
• 3.3.0 - add minification option (thanks @pablohpsilva for the idea)
• 3.2.0 - runs even if inject: false for html-webpack-plugin; supports explicit positioning of style tags; update dependencies
• 3.1.1 - updated README (sorry @rastasheep)
• 3.1.0 - support multiple entry points (thanks @hagmandan); README typos fixed (thanks @eahlberg); updated all dependencies (including webpack 2.2.0)
• v3.0.8 - webpck2 tests moved to webpack 2.2.0-rc3
• v3.0.7 - webpack2 tests moved to webpack 2.2.0-rc.2 and minor fix to maintain compatability
• v3.0.6 - webpack1 tests moved to webpack 1.14.0
• v3.0.5 - updated README after issue 10 (thanks, @Birowsky)
• v3.0.4 - support output.publicPath configuration and better debugging support
• v3.0.3 - instrument code with debug
• v3.0.2 - include lib folder in deployment (thanks, @Aweary)
• v3.0.1 - minor REAME and error handling improvements
• v3.0.0 - complete rewrite to piggback off ExtractTextPlugin
• v2.0.5 - modified test to use dynavers with webpack 1.13.2 and 2.1.0-beta.16
• v2.0.4 - fixed jasmine dependency to explicit version v2.4.1 due to bug in v2.5
• v2.0.3 - updated dependency versions, reclassified some dependencies
• v2.0.2 - merged pull request by 7pass fixing 2.0.1 - thanks!
• v2.0.1 - added explicit guard against use of devtool eval option
• v2.0.0 - webpack 1.x and 2.x compatible, including hot reloading
• v2.0.0.beta.3 - warnings about beta testing (!), debug enhancements, and better unescaping
• v2.0.0.beta.2 - Travis timeout and tag spacing fixes
• v2.0.0-beta.1 - node 4.x fix and fixed handling of multiple scripts
• v2.0.0-beta.0 - hot module reload working (with HtmlWebpackPlugin cache switched off)
• v1.1.1 - hot module reload not working with webpack 2
• v1.1.0 - now Webpack 2.x compatible
• v1.0.7 - added warning that not compatible with Webpack 2
• v1.0.6 - updated tests to match changes in script-ext-html-webpack-plugin
• v1.0.5 - updated code to match changes in semistandard
• v1.0.4 - added debug options
• v1.0.3 - documentation update
• v1.0.2 - documentation update
• v1.0.1 - now plays happily with plugins on same event
• v1.0.0 - initial release