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html-bundler-webpack-plugin

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HTML bundler plugin for webpack handels HTML template as entry point, extracts CSS and JS from their sources specified in HTML.

Package Exports

  • html-bundler-webpack-plugin
  • html-bundler-webpack-plugin/src/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (html-bundler-webpack-plugin) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme


HTML Bundler Plugin for Webpack

The plugin make easily to bundle HTML pages from templates, source styles and scripts

npm node node codecov node

🚀 The best modern alternative to html-webpack-plugin.

This plugin allows to use an HTML template as a starting point for all dependencies used in your web application. All source files of scripts, styles, images specified in HTML are processed automatically. All processed files are extracted and saved to the output directory. The plugin automatically substitutes the output filenames of the processed resources in the generated HTML file.

💡 Highlights

  • An entry point is an HTML template.
  • Source scripts and styles can be specified directly in HTML using <script> and <link> tags.
  • Resolving source assets specified in standard attributes href src srcset etc.
  • Inline JS, CSS, SVG, PNG without additional plugins and loaders.
  • Using template engines Eta, EJS, Handlebars, Nunjucks, LiquidJS and others without template loaders.
  • Support for both async and sync preprocessor

✅ Profit

You specify all the source scripts and styles in one right place (in HTML), instead of defining them in many non-logic places: defining JS files in Webpack Entry, importing SCSS into a JS file.

❓If you have discovered a bug or have a feature suggestion, feel free to create an issue on GitHub.

Simple usage example

Add source scripts and styles directly to HTML:

<html>
<head>
  <!-- load source styles here -->
  <link href="./style.scss" rel="stylesheet">
  <!-- load source scripts here and/or in body -->
  <script src="./main.js" defer="defer"></script>
</head>
<body>
  <h1>Hello World!</h1>
  <img src="./logo.png">
</body>
</html>

The generated HTML contains the output filenames of the processed source files, while the script and link tags remain in place:

<html>
<head>
  <link href="/assets/css/style.05e4dd86.css" rel="stylesheet">
  <script src="/assets/js/main.f4b855d8.js" defer="defer"></script>
</head>
<body>
  <h1>Hello World!</h1>
  <img src="/assets/img/logo.58b43bd8.png">
</body>
</html>

Add the HTML templates in the entry option (syntax is identical to Webpack entry):

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      entry: {
        // define templates here
        index: 'src/views/home/index.html', // output dist/index.html
        'pages/about': 'src/views/about/index.html', // output dist/pages/about.html
      },
    }),
  ],
  // ... loaders for styles, images, etc.
};

See the complete Webpack configuration.

How to create multiple HTML pages with html-bundler-webpack-plugin, see the boilerplate.

Contents

  1. Features
  2. Install and Quick start
  3. Webpack options
  4. Plugin options
  5. Loader options
  6. Template engines
  7. Setup HMR live reload
  8. Recipes

Features

  • HTML template is the entry point for all resources
  • extracts CSS from source style specified in HTML via a <link> tag
  • extracts JS from source script specified in HTML via a <script> tag
  • resolves source files in the CSS url() and in HTML attributes
  • extracts resolved resources to output directory
  • generated HTML contains output filenames
  • support the module types asset/resource asset/inline asset
  • inline CSS in HTML
  • inline JavaScript in HTML
  • inline image as base64 encoded data-URL for PNG, JPG, etc. in HTML and CSS
  • inline SVG as SVG tag in HTML
  • inline SVG as utf-8 data-URL in CSS
  • support the auto publicPath
  • enable/disable extraction of comments to *.LICENSE.txt file
  • supports all JS template engines such as Eta, EJS, Handlebars, Nunjucks, LiquidJS and others
  • minification of generated HTML

Just one HTML bundler plugin replaces the most used functionality of the plugins and loaders:

Package Features
html-webpack-plugin creates HTML and inject script tag for compiled JS file into HTML
mini-css-extract-plugin injects link tag for processed CSS file into HTML
webpack-remove-empty-scripts removes generated empty JS files
html-loader exports HTML
html-webpack-inline-source-plugin inline JS and CSS into HTML from sources
style-loader injects an inline CSS into HTML
posthtml-inline-svg injects an inline SVG icon into HTML
resolve-url-loader resolves a relative URL in CSS
svg-url-loader encodes a SVG data-URL as utf8

Install and Quick start

Install the html-bundler-webpack-plugin:

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

Install additional packages for styles:

npm install css-loader sass sass-loader --save-dev

For example, there is a template ./src/views/home/index.html:

<html>
<head>
  <title><%= title %></title>
  <link href="./style.scss" rel="stylesheet">
  <script src="./main.js" defer="defer"></script>
</head>
<body>
  <h1>Hello <%= name %>!</h1>
  <img src="./logo.png">
</body>
</html>

To compile this template use the following Webpack configuration:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      entry: {
        // define templates here
        index: { // => dist/index.html (key is output filename w/o '.html')
          import: 'src/views/home/index.html', // template file
          data: { title: 'Homepage', name: 'Heisenberg' } // pass variables into template
        },
      },
      js: {
        // output filename of extracted JS from source script loaded in HTML via `<script>` tag
        filename: 'assets/js/[name].[contenthash:8].js',
      },
      css: {
        // output filename of extracted CSS from source style loaded in HTML via `<link>` tag
        filename: 'assets/css/[name].[contenthash:8].css',
      },
    }),
  ],
  module: {
    rules: [
      // styles
      {
        test: /\.(css|sass|scss)$/,
        use: ['css-loader', 'sass-loader'],
      },
      // images
      {
        test: /\.(ico|png|jp?g|svg)/,
        type: 'asset/resource',
        generator: {
          filename: 'assets/img/[name].[hash:8][ext][query]',
        },
      },
    ],
  },
};

Note

No additional template loader required. The plugin handels EJS-like templates automatically. If you use non-EJS-like templates (e.g. Handlebars), see the preprocessor option to use any template engine.

Note

To define the JS output filename, use the js.filename option of the plugin, don't use Webpack's output.filename. Both places have the same effect, but js.filename has priority over output.filename.

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Webpack options

Important Webpack options used to properly configure this plugin.

output.path

Type: string Default: path.join(process.cwd(), 'dist')

The root output directory for all processed files, as an absolute path.
You can omit this option, then all generated files will be saved under dist/ in your project directory.

output.publicPath

Type: string|function Default: auto

The value of the option is prefixed to every URL created by this plugin. If the value is not the empty string or auto, then the option must end with /.

The possible values:

  • publicPath: 'auto' - automatically determines a path of an asset relative of their issuer. The generated HTML page can be opened directly form the local directory and all js, css and images will be loaded in a browser.
  • publicPath: '' - a path relative to an HTML page, in the same directory. The resulting path is different from a path generated with auto.
  • publicPath: '/' - a path relative to document root directory on a server
  • publicPath: '/assets/' - a sub path relative to document root directory on a server
  • publicPath: '//cdn.example.com/' - an external URL with the same protocol (http:// or https://)
  • publicPath: 'https://cdn.example.com/' - an external URL with the https:// protocol only

output.filename

Type: string|function Default: [name].js

The output name of a generated JS file.
Highly recommended to define the filename in the Plugin option js.filename.

The output name of a generated CSS file is determined in the Plugin option css.filename.

Define output JS and CSS filenames in the Plugin option, in one place:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      js: {
        // define the output name of a generated JS file here
        filename: 'assets/js/[name].[contenthash:8].js',
      },
      css: {
        // define the output name of a generated CSS file here
        filename: 'assets/css/[name].[contenthash:8].css',
      },
    }),
  ],
};

entry

The starting point to build the bundle.

Note

Using this plugin an entry point is an HTML template. All script and style source files must be specified in the HTML template.

You can use the Webpack entry option to define HTML templates, but it is highly recommended to define all templates in plugin option entry, because it has an additional data property (not available in the Webpack entry) to pass custom variables into the HTML template.

For details see the plugin option entry.

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Plugin options

test

Type: RegExp Default: /\.(html|ejs|eta)$/

The test option allows to handel only those templates as entry points that match the name of the source file.

For example, if you has *.html and *.hbs templates as entry points, then you can set the option to match all used files: test: /\.(html|hbs)$/.

Why is it necessary to define it? Can't it be automatically processed?

This plugin is very powerful and has many experimental features not yet documented. One of the next features will be the processing scripts and styles as entry points for library bundles without templates. To do this, the plugin must differentiate between a template entry point and a script/style entry point. This plugin can completely replace the functionality of mini-css-extract-plugin and webpack-remove-empty-scripts in future.

If all your templates have .html, .ejs or .eta extensions you don't need to specify the test option.

entry

Type: object is identical to Webpack entry plus additional data property to pass custom variables into the HTML template.

Define all your HTML templates in the entry option.

An HTML template is a starting point for collecting all the dependencies used in your web application. Specify source scripts (JS, TS) and styles (CSS, SCSS, LESS, etc.) directly in HTML. The plugin automatically extracts JS and CSS whose source files are specified in an HTML template.

Simple syntax

The key of an entry object is the output file w/o extension, relative by the outputPath option.
The value is the source file, absolute or relative by the Webpack config file. 

{
  entry: {
    index: 'src/views/home/index.html', // => dist/index.html
    'pages/about/index': 'src/views/about.html', // => dist/pages/about/index.html
  },
}

Advanced syntax

The entry value might be an object:

type entryValue = {
  import: string,
  filename: string
  data: object,
}
  • import - a source file, absolute or relative by the Webpack config file
  • filename - an output file, relative by the 'outputPath' option
  • data - an object passed into preprocessor to render a template with variables

Usage example:

{
  entry: {
    // output ./dist/pages/about/index.html
    'pages/about/index': { // output file as the key
      import: 'src/views/about.html',
      data: {
        title: 'About',
      }
    },

    // output ./dist/pages/contact/index.html
    contact: {
      import: 'src/views/contact.html',
      filename: 'pages/contact/index.html', // output file as the 'filename' property
    },
  },
}

Note

You can define templates both in Webpack entry and in the entry option of the plugin. The syntax is identical. But the data property can only be defined in the entry option of the plugin.

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outputPath

Type: string Default: webpack.options.output.path

The output directory for processed file. This directory can be relative by webpack.options.output.path or absolute.

filename

Type: string | Function Default: [name].html

The output filename relative by the outputPath option.

  • If type is string then following substitutions (see output.filename for chunk-level) are available in template string:
    • [id] The ID of the chunk.
    • [name] Only filename without extension or path.
    • [contenthash] The hash of the content.
    • [contenthash:nn] The nn is the length of hashes (defaults to 20).
  • If type is Function then following arguments are available in the function:
    • @param {PathData} pathData has the useful properties (see the type PathData):
      • pathData.filename the full path to source file
      • pathData.chunk.name the name of entry key
    • @param {AssetInfo} assetInfo Mostly this object is empty.
    • @return {string} The name or template string of output file.

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css

Type: Object
Default properties:

{
  test: /\.(css|scss|sass|less|styl)$/,
  filename: '[name].css',
  outputPath: null,
  verbose: false,
}
  • test - an RegEpx to process all source styles that pass test assertion
  • filename - an output filename of extracted CSS. Details see by filename option.\
  • outputPath - an output path of extracted CSS. Details see by outputPath option.
  • verbose - enable/disable display process information for styles

This is the option to extract CSS from a style source file specified in the HTML tag:

<link href="./style.scss" rel="stylesheet">

Warning

Don't import source styles in JavaScript! Styles must be specified directly in HTML. Don't define source JS files in Webpack entry! Scripts must be specified directly in HTML.

The default CSS output filename is [name].css. You can specify your own filename using webpack filename substitutions:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      css: {
        filename: 'assets/css/[name].[contenthash:8].css',
      },
    }),
  ],
};

The [name] is the base filename of a loaded style. For example, if source file is style.scss, then output filename will be assets/css/style.1234abcd.css.
If you want to have a different output filename, you can use the filename options as the function.

Warning

Don't use mini-css-extract-plugin or style-loader, they are not required more.
The html-bundler-webpack-plugin extracts CSS much faster than other plugins and resolves all asset URLs in CSS, therefore the resolve-url-loader is redundant too.

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js

Type: Object
Default properties:

{
  filename: '[name].js', 
  outputPath: null,
  verbose: false,
}
  • filename - an output filename of extracted JS. Details see by filename option.\
  • outputPath - an output path of extracted CSS. Details see by outputPath option.
  • verbose - enable/disable display process information for styles

The test property absent because all JS files specified in <script> tag are automatically detected.

This is the option to extract JS from a script source file specified in the HTML tag:

<script src="./main.js"></script>

The default JS output filename is [name].js. You can specify your own filename using webpack filename substitutions:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      js: {
        filename: 'assets/js/[name].[contenthash:8].js',
      },
    }),
  ],
};

The [name] is the base filename script. For example, if source file is main.js, then output filename will be assets/js/main.1234abcd.js.
If you want to have a different output filename, you can use the filename options as the function.

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postprocess

Type:

type postprocess = (
  content: string,
  info: ResourceInfo,
  compilation: Compilation,
) => string|null;

type ResourceInfo = {
  verbose: boolean,
  isEntry: boolean,
  filename: 
    | string
    | ((pathData: PathData) => string),
  sourceFile: string,
  outputPath: string,
  assetFile: string,
};

Default: null

Called after a source of an asset module is rendered, but not yet processed by other plugins.

The postprocess have the following arguments:

  • content: string - a content of processed file
  • info: ResourceInfo - an info about current file
  • compilation: Compilation - the Webpack compilation object

The ResourceInfo have the following properties:

  • verbose: boolean - whether information should be displayed
  • isEntry: boolean - if is true, the resource is the entry point, otherwise is a resource loaded in the entry point
  • filename: string|function - a filename of the resource, see filename
  • sourceFile: string - a full path of the source file
  • outputPath: string - a full path of the output directory
  • assetFile: string - an output asset file relative by outputPath

Return new content as a string. If return null, the result processed via Webpack plugin is ignored and will be saved a result processed via the loader.

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minify

Type: Object|string|boolean Default: false

For minification generated HTML is used the html-minifier-terser with the following default options:

{
  collapseWhitespace: true,
  keepClosingSlash: true,
  removeComments: true,
  removeRedundantAttributes: true,
  removeScriptTypeAttributes: true,
  removeStyleLinkTypeAttributes: true,
  useShortDoctype: true,
  minifyCSS: true,
  minifyJS: true,
}

Possible values:

  • false - the default value disable minification
  • true - enable minification with default options
  • auto - in development mode disable minification, in production mode enable minification
  • {} - the object to set custom options, this object are merged with default options, see options reference

extractComments

Type: boolean Default: false

Enable/disable extracting comments from source scripts to the *.LICENSE.txt file.

When using splitChunks optimization for node modules containing comments, Webpack extracts those comments into a separate text file. By default, the plugin don't create such unwanted text files. But if you want to extract files like *.LICENSE.txt, set this option to true.

verbose

Type: boolean Default: false

Display information about all processed files.

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watchFiles

Type:

type watchFiles = {
  paths?: Array<string>;
  files?: Array<RegExp>;
  ignore?: Array<RegExp>;
}

Default:

watchFiles: {
  paths: ['./'], // projeckt root directory
  files: [], // if empty, watch all files in `paths`, except `ignore`
  ignore: [
    /[\\/](node_modules|dist|test)$/, // ignore standard project dirs
    /[\\/]\..+$/, // ignore hidden dirs and files, e.g.: .git, .idea, .gitignore, etc.
    /package(?:-lock)*.json$/, // ingnore npm files
    /webpack\.(.+)\.js$/, // ignore Webpack config files
    /\.(je?pg|png|ico|webp|svg|woff2?|ttf|otf|eot)$/, // ignore binary assets
  ],
}

Allow to configure paths and files to watch file changes in watchor serv mode.

Properties:

  • paths - A list of relative or absolute paths to directories where should be watched files.
  • files - Watch the files specified in paths, except ignore, that match the regular expressions.
  • ignore - Ignore the specified paths or files, that match the regular expressions.

To reduce CPU or memory usage, it is recommended to at least specify the source files directory in the paths.

For example, your project contains many files and folders in the project directory, while all source files are in ./src/ directory, then add it to the paths:

watchFiles: {
  paths: ['src'],
},

If the source directory contains many binary files, e.g. .pdf .mov .wav etc., then add them to the ignore:

watchFiles: {
  paths: ['src'],
  ignore: [
    /\.(pdf|mov|wav)$/,
  ]
},

or you can add the whole folders to the ignore, e.g.:

watchFiles: {
  paths: ['src'],
  ignore: [
    /[\\/]src[\\/]audio/,
    /[\\/]src[\\/]image/,
    /[\\/]src[\\/]video/,
  ]
},

Please consider already ignored files by default, see above.

If the source directory contains too many subdirectories and different types of files, then you can specify only those files that should be watched.

watchFiles: {
  paths: ['src'],
  files: [
    /\.(html|ejs|ts|js|scss|css)$/,
  ]
},

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Loader options

The default loader:

{
  test: /.(html|ejs|eta)$/,
  loader: HtmlBundlerPlugin.loader,
}

You can omit the loader in Webpack modules.rules. If the HtmlBundlerPlugin.loader is not configured, the plugin add it with default options automatically.

The default loader handels HTML files and EJS-like templates.

Warning

The plugin works only with the own loader HtmlBundlerPlugin.loader. Do not use another loader. This loader replaces the functionality of html-loader.

sources

Type:

type sources =
  | boolean
  | Array<{
      tag?: string;
      attributes?: Array<string>;
      filter?: ({
        tag: string,
        attribute: string,
        value: string,
        attributes: string,
        resourcePath: string
      }) => boolean|undefined;
    }>;

Default: true

By default, resolves source files in the following tags and attributes:

Tag Attributes
link href (for type="text/css" or rel="stylesheet") imagesrcset (for as="image")
script src
img src srcset
image href
use href
input src (for type="image")
source src srcset
audio src
track src
video src poster
object data

Warning

Don't use the deprecated xlink:href attribute by the image and use tags.

The filter is called for all attributes of the tag defined as defaults and in sources option. The argument is an object containing the properties:

  • tag: string - a name of the HTML tag
  • attribute: string - a name of the HTML attribute
  • value: string - a value of the HTML attribute
  • attributes: string - all attributes of the tag
  • resourcePath: string - a path of the HTML template

The processing of an attribute can be ignored by returning false.

To disable the processing of all attributes, set the sources option as false.

Note

Automatically are processed only attributes containing a relative path or Webpack alias:

  • src="./image.png" or src="image.png" - an asset in the local directory
  • src="../../assets/image.png" - a relative path to parent directory
  • src="@images/image.png" - an image directory as Webpack alias

Url values are not processed:

  • src="https://example.com/img/image.png"
  • src="//example.com/img/image.png"
  • src="/img/image.png"

Others not file values are ignored, e.g.:

  • src="data:image/png; ..."
  • src="javascript: ..."

Examples of using argument properties:

{
  tag: 'img',
  // use the destructuring of variables from the object argument  
  filter: ({ tag, attribute, value, attributes, resourcePath }) => {
    if (attribute === 'src') return false;
    if (value.endsWith('.webp')) return false;
    if ('srcset' in attributes && attributes['srcset'] === '') return false;
    if (resourcePath.indexOf('example')) return false;
    // otherwise return 'true' or nothing to allow processing
  },
}

The default sources can be extended with new tags and attributes.

For example, add the processing of the data-src and data-srcset attributes to the img tag:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
module.exports = {
  module: {
    rules: [
      {
        test: /\.html$/,
        loader: HtmlBundlerPlugin.loader,
        options: {
          sources: [
            {
              tag: 'img',
              attributes: ['data-src', 'data-srcset'],
            }
          ],
        },
      },
    ],
  },
};

You can use the filter function to allow the processing only specific attributes.

For example, allow processing only for images in content attribute of the meta tag:

<html>
<head>
  <!-- ignore the attribute via filter -->
  <meta name="theme-color" content="#ffffff">
  <!-- resolve the 'content' attribute if 'name' containing special values  -->
  <meta name="twitter:image" content="./image.png">
  <meta name="logo" content="./logo.png">
</head>
<body>
  <!-- resolve 'src' attribute containing relative path -->
  <img src="./image.png">
</body>
</html>

webpack.config.js

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
module.exports = {
  module: {
    rules: [
      {
        test: /\.html$/,
        loader: HtmlBundlerPlugin.loader,
        options: {
          sources: [
            {
              tag: 'meta',
              attributes: ['content'],
              // handles an image in the 'content' attrubute of the 'meta' tag 
              // when the 'name' attribute is one of: twitter:image, logo
              filter: ({ attributes }) => {
                const allowedNames = ['twitter:image', 'logo'];
                if ('name' in attributes && allowedNames.indexOf(attributes.name) < 0) {
                  return false;
                }
              },
            }
          ],
        },
      },
    ],
  },
};

The filter can disable an attribute of a tag.

For example, disable the processing of default attribute srcset of the img tag:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
module.exports = {
  module: {
    rules: [
      {
        test: /\.html$/,
        loader: HtmlBundlerPlugin.loader,
        options: {
          sources: [
            {
              tag: 'img',
              filter: ({ attribute }) => attribute !== 'srcset',
            }
          ],
        },
      },
    ],
  },
};

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preprocessor

Type:

type preprocessor = (
  template: string,
  loaderContext: LoaderContext
) => string|Promise;

The default preprocessor use the Eta templating engine:

const config = {
  // defaults async is false, because the `includeFile()` function is sync,
  // wenn async is true then must be used `await includeFile()`
  async: false,
  useWith: true, // to use data in template without `it.` scope
  root: process.cwd(),
};
preprocessor = (template, { data }) => Eta.render(template, data, config);

Note

The Eta has the same EJS syntax, is only 2KB gzipped and is much fasted than EJS.

The template is the raw content of a template file defined in the entry option.
The loaderContext is the Loader Context object contained useful properties:

  • mode: string - a Webpack mode: production, development, none
  • rootContext: string - a path to Webpack context
  • resource: string - a template file, including query
  • resourcePath: string - a template file
  • data: object|null - variables passed form entry

The preprocessor is called for each entry file, before processing of the content. This function can be used to compile the template with a template engine, such as Eta, EJS, Handlebars, Nunjucks, etc.

Return new content as a string or Promise for async processing.

The usage example for your own sync render function:

{
  preprocessor: (template, { data }) => render(template, data)
}

The example of using Promise for your own async render function:

{
  preprocessor: (template, { data }) =>
    new Promise((resolve) => {
      const result = render(template, data);
      resolve(result);
    })
}

You can use variables in the template with the EJS syntax:

<html>
<body>
  <h1>Hello <%= name %>!</h1>
</body>
</html>

To pass variables in the template use the data property:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      entry: {
        index: { // => dist/index.html
          import: './src/views/index.html',
          data: { name: 'Heisenberg' } // <= pass data into template via preprocessor
        },
      },
    }),
  ],
  module: {
    rules: [
      // for EJS-like templates the HtmlBundlerPlugin.loader can be omitted
      // add here loaders for styles, images, etc.
    ],
  },
};

Note

The plugin supports EJS-like templates "out of the box" therefore the HtmlBundlerPlugin.loader can be omitted in the Webpack config.

Here is an example using a non-default Mustache-like template syntax:

<html>
<body>
  <h1>Hello {{ name }}!</h1>
</body>
</html>

Add the preprocessor to use your custom template engine:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const Handlebars = require('handlebars');

module.exports = {
  // ...
  module: {
    rules: [
      {
        test: /\.html$/,
        loader: HtmlBundlerPlugin.loader,
        options: {
          preprocessor: (template, { data }) => Handlebars.compile(template)(data),
        },
      },
    ],
  },
};

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Template engines

Using the preprocessor, you can compile any template with a template engine such as:

Note

For Pug templates use the pug-plugin. This plugin works on the same codebase but has additional Pug-specific options and features.

Using the Eta

Supported "out of the box"

Eta is compatible* with EJS syntax, is smaller and faster than EJS.

For example, there is the template index.eta

<html>
<body>
  <h1>{{ headline }}!</h1>
  <ul class="people">
    <% for (let i = 0; i < people.length; i++) {%>
    <li><%= people[i] %>></li>
    <% } %>
  </ul>
  <%~ includeFile('/src/views/partials/footer') %>
</body>
</html>

Add the template compiler to preprocessor:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const Eta = require('eta');

const EtaConfig = {
  // defaults async is false, because the `includeFile()` function is sync,
  // wenn async is true then must be used `await includeFile()`
  async: false,
  useWith: true, // to use data in template without `it.` scope
  root: process.cwd(),
};

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      test: /\.(html|ejs|eta)$/, // <= change
      entry: {
        index: {
          import: './src/index.eta',
          data: {
            headline: 'Breaking Bad',
            people: ['Walter White', 'Jesse Pinkman'],
          },
        },
      },
    }),
  ],
  module: {
    rules: [
      {
        test: /\.(html|ejs|eta)$/, // <= change
        loader: HtmlBundlerPlugin.loader,
        options: {
          preprocessor: (template, { data }) => Eta.render(template, data, EtaConfig), // <= change
        },
      },
    ],
  },
};

Note

The default loader already support the Eta. You can omit it in Webpack config.

Warning

For compatibility the Eta compiler with the EJS templates, the default preprocessor use the useWith: true Eta option to use variables in template without the Eta-specific it. scope

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Using the EJS

Basic support "out of the box"

For example, there is the template index.ejs

<html>
<body>
  <h1>{{ headline }}!</h1>
  <ul class="people">
    <% for (let i = 0; i < people.length; i++) {%>
    <li><%= people[i] %>></li>
    <% } %>
  </ul>
  <%- include('/src/views/partials/footer.html'); %>
</body>
</html>

Add the template compiler to preprocessor:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const ejs = require('ejs');

// create EJS config
const ejsConfig = {
  root: process.cwd(), // define root template path when using `include()`
  async: true, // optional, async rendering
  
}

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      test: /\.(html|ejs)$/, // <= change
      entry: {
        index: {
          import: './src/index.ejs',
          data: {
            headline: 'Breaking Bad',
            people: ['Walter White', 'Jesse Pinkman'],
          },
        },
      },
    }),
  ],
  module: {
    rules: [
      {
        test: /\.(html|ejs)$/, // <= change
        loader: HtmlBundlerPlugin.loader,
        options: {
          preprocessor: (template, { data }) => ejs.render(template, data, ejsConfig), // <= change
        },
      },
    ],
  },
};

Note

The default loader already support the simple syntax of EJS. You can omit it in Webpack config when you don't use include().

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Using the Handlebars

For example, there is the template index.hbs

<html>
<body>
  <h1>{{ headline }}!</h1>
  <ul class="people">
    {{#each people}}
    <li>{{this}}</li>
    {{/each}}
  </ul>
</body>
</html>

Add the template compiler to preprocessor:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const Handlebars = require('handlebars');

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      test: /\.(html|hbs)$/, // add the option to match *.hbs files in entry
      entry: {
        index: { // output dist/imdex.html
          import: './src/index.hbs',
          // pass data into the preprocessor
          data: {
            headline: 'Breaking Bad',
            people: ['Walter White', 'Jesse Pinkman'],
          },
        },
      },
    }),
  ],
  module: {
    rules: [
      {
        test: /\.(html|hbs)$/, // must match the files specified in the entry
        loader: HtmlBundlerPlugin.loader,
        options: {
          // compiles *.hbs files to HTML
          preprocessor: (template, { data }) => Handlebars.compile(template)(data),
        },
      },
    ],
  },
};

Note

If you use a template with a specific extension other than .html .ejs or .eta, specify that extension in the test option of the plugin.

For example, when using the Handlebars template with .hbs extension:

new HtmlBundlerPlugin({
  test: /\.(html|hbs)$/, // <= specify all extensions used in entry
  entry: {
    index: './src/views/home.hbs',
  },
})

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Using the Mustache

For example, there is the template index.mustache

<html>
<body>
  <h1>{{ headline }}</h1>
  <ul class="people">
    {{#people}}
    <li>{{.}}</li>
    {{/people}}
  </ul>
</body>
</html>

Change Webpack config according to:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const Mustache = require('mustache');

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      test: /\.(html|mustache)$/, // <= change
      index: {
        import: './src/index.mustache',
        data: {
          headline: 'Breaking Bad',
          people: ['Walter White', 'Jesse Pinkman'],
        },
      },
    }),
  ],
  module: {
    rules: [
      {
        test: /\.(html|mustache)$/, // <= change
        loader: HtmlBundlerPlugin.loader,
        options: {
          preprocessor: (template, { data }) => Mustache.render(template, data), // <= change
        },
      },
    ],
  },
};

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Using the Nunjucks

For example, there is the template index.njk

<html>
<body>
  <h1>{{ headline }}!</h1>
  <ul class="people">
    {% for name in people %}
    <li class="name">{{ name }}</li>
    {% endfor %}
  </ul>
</body>
</html>

Add the template compiler to preprocessor:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const Nunjucks = require('nunjucks');

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      test: /\.(html|njk)$/, // <= change
      entry: {
        index: {
          import: './src/index.njk',
          data: {
            headline: 'Breaking Bad',
            people: ['Walter White', 'Jesse Pinkman'],
          },
        },
      },
    }),
  ],
  module: {
    rules: [
      {
        test: /\.(html|njk)$/, // <= change
        loader: HtmlBundlerPlugin.loader,
        options: {
          preprocessor: (template, { data }) => Nunjucks.renderString(template, data), // <= change
        },
      },
    ],
  },
};

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Using the LiquidJS

For example, there is the template index.liquidjs

<html>
<body>
  <h1>{{ headline }}!</h1>
  <ul class="people">
    {% for name in people %}
    <li class="name">{{ name }}</li>
    {% endfor %}
  </ul>
</body>
</html>

Add the template compiler to preprocessor:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const { Liquid } = require('liquidjs');

const LiquidEngine = new Liquid();

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      test: /\.(html|liquidjs)$/, // <= change
      entry: {
        index: {
          import: './src/index.liquidjs',
          data: {
            headline: 'Breaking Bad',
            people: ['Walter White', 'Jesse Pinkman'],
          },
        },
      },
    }),
  ],
  module: {
    rules: [
      {
        test: /\.(html|liquidjs)$/, // <= change
        loader: HtmlBundlerPlugin.loader,
        options: {
          // async parseAndRender method return promise
          preprocessor: (content, { data }) => LiquidEngine.parseAndRender(content, data), // <= change
        },
      },
    ],
  },
};

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Setup HMR live reload

To enable live reload by changes any file add in the Webpack config the devServer option:

module.exports = {
  // enable HMR with live reload
  devServer: {
    static: {
      directory: path.join(__dirname, 'dist'),
    },
    watchFiles: {
      paths: ['src/**/*.*'],
      options: {
        usePolling: true,
      },
    },
  },
};

Note

Live reload works only if in HTML used a JS file. This is specific of Webpack. If your HTML has not a JS, then create one empty JS file, e.g. hmr.js and add it in the HTML:

<script src="./hmr.js"></script>

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How to use source images in HTML

Add to Webpack config the rule:

module: {
  rules: [
    {
      test: /\.(png|jpe?g|ico|svg)$/,
      type: 'asset/resource',
      generator: {
        filename: 'assets/img/[name].[hash:8][ext]',
      },
    },
  ],
}

Add a source file using a relative path or Webpack alias in HTML:

<html>
<head>
  <link href="./favicon.ico" rel="icon" />
</head>
<body>
  <img src="./apple.png" srcset="./apple1.png 320w, ./apple2.png 640w" alt="apple">
  <picture>
    <source srcset="./fig1.jpg, ./fig2.jpg 320w, ./fig3.jpg 640w">
  </picture>
</body>
</html>

The generated HTML contains hashed output images filenames:

<html>
<head>
  <link href="/assets/img/favicon.05e4dd86.ico" rel="icon" />
</head>
<body>
  <img src="/assets/img/apple.f4b855d8.png" srcset="/assets/img/apple1.855f4bd8.png 320w, /assets/img/apple2.d8f4b855.png 640w" alt="apple">
  <picture>
    <source srcset="/assets/img/fig1.605e4dd8.jpg, /assets/img/fig2.8605e4dd.jpg 320w, /assets/img/fig3.e4605dd8.jpg 640w">
  </picture>
</body>
</html>

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How to resize and generate responsive images

To resize or generate responsive images is recommended to use the responsive-loader.

Install additional packages:

npm i -D responsive-loader sharp

To resize an image use the query parameter size:

<!-- resize source image to max. 640px -->
<img src="./image.png?size=640">

To generate responsible images use in srcset attribute the query parameter sizes als JSON5 to avoid parsing error, because many images must be separated by commas , but we use the comma to separate sizes for one image:

<!-- responsible images with different sizes: 320px, 480px, 640px -->
<img src="./image.png?size=480"
     srcset="./image.png?{sizes:[320,480,640]}">

You can convert source image to other output format. For example, we have original image 2000px width as PNG and want to resize to 640px and save as WEBP:

<img src="./image.png?size=640&format=webp">

You can create a small inline image placeholder. To do this, use the following query parameters:

  • placeholder=true - enable to generate the placeholder
  • placeholderSize=35 - the size of the generating placeholder
  • prop=placeholder - the plugin-specific prop parameter retrieves the property from the object generated by responsive-loader
<img src="./image.png?placeholder=true&placeholderSize=35&prop=placeholder"
     srcset="./image.png?{sizes:[320,480,640]}">

The generated HTML:

<img src="data:image/png;base64,iVBORw0K ..."
     srcset="/img/image-320w.png 320w,/img/image-480w.png 480w,/img/image-640w.png 640w">

Add to Webpack config the rule for responsive images:

module.exports = {
  module: {
    rules: [
      {
        test: /\.(png|jpe?g|webp)$/,
        type: 'asset/resource',
        use: {
          loader: 'responsive-loader',
          options: {
            // output filename of images, e.g. dist/assets/img/image-640w.png
            name: 'assets/img/[name]-[width]w.[ext]',
            sizes: [640], // max. image size, if 'size' query is not used
          },
        },
      },
      // ... other loaders
    ],
  },
};

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How to preload source fonts in HTML

Add to Webpack config the rule:

module: {
  rules: [
    {
      test: /\.(eot|ttf|woff|woff2)$/,
      type: 'asset/resource',
      generator: {
        filename: 'assets/fonts/[name][ext]',
      },
    },
  ],
}

Add a source file using a relative path or Webpack alias in HTML:

<html>
<head>
  <link href="./font1.woff2" rel="preload" as="font" type="font/woff2" />
  <link href="./font2.woff2" rel="preload" as="font" type="font/woff2" />
</head>
<body>
  <h1>Hello World!</h1>
</body>
</html>

The generated HTML contains output fonts filenames:

<html>
<head>
  <link href="/assets/fonts/font1.woff2" rel="preload" as="font" type="font/woff2" />
  <link href="/assets/fonts/font2.woff2" rel="preload" as="font" type="font/woff2" />
</head>
<body>
  <h1>Hello World!</h1>
</body>
</html>

Note

You don't need a plugin to copy files from source directory to public.

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How to inline CSS in HTML

For example, the style.scss:

$color: red;
h1 {
  color: $color;
}

Add the ?inline query to the source filename which you want to inline:

<html>
<head>
  <!-- load style as file -->
  <link href="./main.scss" rel="stylesheet" />
  <!-- inline style -->
  <link href="./style.scss?inline" rel="stylesheet" />
</head>
<body>
  <h1>Hello World!</h1>
</body>
</html>

The generated HTML contains inline CSS already processed via Webpack:

<html>
<head>
  <!-- load style as file -->
  <link href="/assets/css/main.05e4dd86.css" rel="stylesheet">
  <!-- inline style -->
  <style>
    h1{color: red;}
  </style>
</head>
<body>
  <h1>Hello World!</h1>
</body>
</html>

Note

To enable source map in inline CSS set the Webpack option devtool.

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How to inline JS in HTML

For example, the script.js:

console.log('Hello JS!');

Add the ?inline query to the source filename which you want to inline:

<html>
<head>
  <!-- load script as file -->
  <script src="./main.js" defer="defer"></script>
  <!-- inline script -->
  <script src="./script.js?inline"></script>
</head>
<body>
  <h1>Hello World!</h1>
</body>
</html>

The generated HTML contains inline JS already compiled via Webpack:

<html>
<head>
  <!-- load style as file -->
  <script src="assets/js/main.992ba657.js" defer="defer"></script>
  <!-- inline script -->
  <script>
    (()=>{"use strict";console.log("Hello JS!")})();
  </script>
</head>
<body>
  <h1>Hello World!</h1>
</body>
</html>

Note

If Webpack is started as serve or watch, the inlined JS code will contain additional HMR code. Don't worry it is ok, so works Webpack live reload.

To enable source map in inline JS set the Webpack option devtool.

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How to inline SVG, PNG images in HTML

You can inline the images in two ways:

  • force inline image using ?inline query
  • auto inline by image size

Add to Webpack config the rule:

module: {
  rules: [
    {
      test: /\.(png|jpe?g|svg|webp|ico)$/i,
      oneOf: [
        // inline image using `?inline` query
        {
          resourceQuery: /inline/,
          type: 'asset/inline',
        },
        // auto inline by image size
        {
          type: 'asset',
          parser: {
            dataUrlCondition: {
              maxSize: 1024,
            },
          },
          generator: {
            filename: 'assets/img/[name].[hash:8][ext]',
          },
        },
      ],
    },
  ],
}

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How to pass data into multiple templates

You can pass variables into template using a template engine, e.g. Handlebars. For multiple page configuration, better to use the Nunjucks template engine maintained by Mozilla.

For example, you have several pages with variables.
Both pages have the same layout src/views/layouts/default.html

<!DOCTYPE html>
<html>
<head>
  <title>{{ title }}</title>
  <!-- block for specific page styles -->
  {% block styles %}{% endblock %}
  <!-- block for specific page scripts -->
  {% block scripts %}{% endblock %}
</head>
<body>
  <main class="main-content">
    <!-- block for specific page content -->
    {% block content %}{% endblock %}
  </main>
</body>
</html>

src/views/pages/home/index.html

{% extends "src/views/layouts/default.html" %}

{% block styles %}
  <!-- load source style -->
  <link href="./home.scss" rel="stylesheet">
{% endblock %}

{% block scripts %}
  <!-- load source script -->
  <script src="./home.js" defer="defer"></script>
{% endblock %}

{% block content %}
  <h1>{{ filmTitle }}</h1>
  <p>Location: {{ location }}</p>
  <!-- @images is the Webpack alias for the source images directory -->
  <img src="@images/{{ imageFile }}">
{% endblock %}

src/views/pages/about/index.html

{% extends "src/views/layouts/default.html" %}

{% block styles %}
  <link href="./about.scss" rel="stylesheet">
{% endblock %}

{% block scripts %}
  <script src="./about.js" defer="defer"></script>
{% endblock %}

{% block content %}
  <h1>Main characters</h1>
  <ul>
  {% for item in actors %}
    <li class="name">{{ item.firstname }} {{ item.lastname }}</li>
  {% endfor %}
  </ul>
{% endblock %}

Webpack config

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');
const Nunjucks = require('nunjucks');

// Note: 
// If your pages have a lot of variables, it's a good idea to define them separately 
// to keep the configuration clean and clear.
const entryData = {
  // variables for home page
  home: {
    title: 'Home',
    filmTitle: 'Breaking Bad',
    location: 'Albuquerque, New Mexico',
    imageFile: 'map.png',
  },
  // variables for about page
  about: {
    title: 'About',
    actors: [
      {
        firstname: 'Walter',
        lastname: 'White, "Heisenberg"',
      },
      {
        firstname: 'Jesse',
        lastname: 'Pinkman',
      },
    ],
  },
};

module.exports = {
  resolve: {
    alias: {
      '@images': path.join(__dirname, 'src/assets/images'),
    },
  },
  plugins: [
    new HtmlBundlerPlugin({
      entry: {
        // define your templates here
        index: { // => dist/index.html
          import: 'src/views/pages/home/index.html',
          data: entryData.home,
        },
        about: { // => dist/about.html
          import: 'src/views/pages/about/index.html',
          data: entryData.about,
        },
      },
      js: {
        filename: 'assets/js/[name].[contenthash:8].js',
      },
      css: {
        filename: 'assets/css/[name].[contenthash:8].css',
      },
    }),
  ],
  module: {
    rules: [
      // templates
      {
        test: /\.html/,
        loader: HtmlBundlerPlugin.loader, //  HTML template loader
        options: {
          // render template with page-specific variables defined in entry
          preprocessor: (template, { data }) => Nunjucks.renderString(template, data),
        },
      },
      // styles
      {
        test: /\.(css|sass|scss)$/,
        use: ['css-loader', 'sass-loader'],
      },
      // images
      {
        test: /\.(png|svg|jpe?g|webp)$/i,
        type: 'asset/resource',
        generator: {
          filename: 'assets/img/[name].[hash:8][ext]',
        },
      },
    ],
  },
};

The generated dist/index.html

<!DOCTYPE html>
<html>
<head>
  <title>Home</title>
  <link href="assets/css/home.2180238c.css" rel="stylesheet">
  <script src="assets/js/home.790d746b.js" defer="defer"></script>
</head>
<body>
  <main class="main-content">
    <h1>Breaking Bad</h1>
    <p>Breaking Bad is an American crime drama</p>
    <p>Location: Albuquerque, New Mexico</p>
    <img src="assets/img/map.697ef306.png" alt="location" />
  </main>
</body>
</html>

The generated dist/about.html

<!DOCTYPE html>
<html>
<head>
  <title>About</title>
  <link href="assets/css/about.2777c101.css" rel="stylesheet">
  <script src="assets/js/about.1.c5e03c0e.js" defer="defer"></script>
</head>
<body>
  <main class="main-content">
    <h1>Main characters</h1>
    <ul>
      <li class="name">Walter White, &quot;Heisenberg&quot;</li>
      <li class="name">Jesse Pinkman</li>
    </ul>
  </main>
</body>
</html>

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How to config splitChunks

Webpack tries to split every entry file, include template files, which completely breaks the compilation process in the plugin.

To avoid this issue, you must specify which scripts should be split, using optimization.splitChunks.cacheGroups:

module.exports = {
  optimization: {
    splitChunks: {
      cacheGroups: {
        scripts: {
          test: /\.(js|ts)$/,
          chunks: 'all',
        },
      },
    },
  },
};

Note

In the test option must be specified all extensions of scripts which should be split.

See details by splitChunks.cacheGroups.

For example, in a template are used the scripts and styles from node_modules:

<html>
<head>
  <title>Home</title>
  <link href="bootstrap/dist/css/bootstrap.min.css" rel="stylesheet">
  <script src="bootstrap/dist/js/bootstrap.min.js" defer="defer"></script>
</head>
<body>
  <h1>Hello World!</h1>
  <script src="./main.js"></script>
</body>
</html>

Note

In the generated HTML all script tags remain in their original places and split chunks will be added there, in the order that Webpack generated.

In this use case the optimization.cacheGroups.{cacheGroup}.test option must match exactly only JS files from node_modules:

module.exports = {
  optimization: {
    runtimeChunk: 'single',
    splitChunks: {
      cacheGroups: {
        vendor: {
          test: /[\\/]node_modules[\\/].+\.(js|ts)$/, // use exactly this Regexp
          name: 'vendor',
          chunks: 'all',
        },
      },
    },
  },
};

Warning

Splitting CSS to many chunk is principal impossible. Splitting works only for JS files. If you use vendor styles in your style file, e.g.:

style.scss

@use "bootstrap/scss/bootstrap";
body {
  color: bootstrap.$primary;
}

Then vendor styles will not be saved to a separate file, because sass-loader generates one CSS bundle code. Therefore vendor styles should be loaded in a template separately.

Warning

If you will to use the test as /[\\/]node_modules[\\/], without extension specification, then Webpack concatenates JS code together with CSS in one file, because Webpack can't differentiate CSS module from JS module, therefore you MUST match only JS files.

If you want save module styles separate from your styles, then load them in a template separately:

<html>
<head>
  <title>Home</title>
  <!-- load module styles separately -->
  <link href="bootstrap/dist/css/bootstrap.min.css" rel="stylesheet">
  <!-- load your styles separately -->
  <link href="./style.scss" rel="stylesheet">
</head>
<body>
  <h1>Hello World!</h1>
  <script src="./main.js"></script>
</body>
</html>

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How to split multiple node modules and save under own names

If you use many node modules and want save each module to separate file then use optimization.cacheGroups.{cacheGroup}.name as function.

For example, many node modules are imported in the main.js:

import { Button } from 'bootstrap';
import _, { map } from 'underscore';
// ...

There is a template used the main.js ./src/views/index.html:

<html>
<head>
  <!-- load source script -->
  <script src="./main.js" defer="defer"></script>
</head>
<body>
  <h1>Hello World!</h1>
</body>
</html>

Then, use the optimization.splitChunks.cacheGroups.{cacheGroup}.name as following function:

const HtmlBundlerPlugin = require('html-bundler-webpack-plugin');

module.exports = {
  plugins: [
    new HtmlBundlerPlugin({
      entry: {
        index: 'src/views/index.html',
      },
      js: {
        filename: 'js/[name].[contenthash:8].js',
      },
    }),
  ],
  optimization: {
    runtimeChunk: 'single',
    splitChunks: {
      chunks: 'all',
      minSize: 10000, // extract modules bigger than 10KB, defaults is 30KB
      cacheGroups: {
        vendor: {
          test: /[\\/]node_modules[\\/].+\.(js|ts)$/, // split JS only, ignore CSS modules
          // save chunk under a name
          name(module, chunks, groupName) {
            const moduleName = module.resourceResolveData.descriptionFileData.name.replace('@', '');
            return `${groupName}.${moduleName}`;
          },
        },
      },
    },
  },
};

The split files will be saved like this:

dist/js/vendor.popperjs/core.f96a1152.js <- `popperjs/core` is extracted from bootstrap
dist/js/vendor.bootstrap.f69a4e44.js
dist/js/vendor.underscore.4e44f69a.js
dist/js/runtime.9cd0e0f9.js <- common runtime code
dist/js/script.3010da09.js

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Also See

  • ansis - The Node.js lib for ANSI color styling of text in terminal
  • pug-loader The Pug loader for Webpack
  • pug-plugin The Pug plugin for Webpack

License

ISC