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HTML Webpack Plugin

Plugin that simplifies creation of HTML files to serve your bundles

Install

  npm i --save-dev html-webpack-plugin

  yarn add --dev 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.

Sponsors

Thanks for supporting the ongoing improvements to the html-webpack-plugin!

Zero Config

The html-webpack-plugin works without configuration.
It's a great addition to the ⚙️ webpack-config-plugins.

Plugins

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

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:

webpack.config.js

const HtmlWebpackPlugin = require('html-webpack-plugin')

module.exports = {
  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 mini-css-extract-plugin) then these will be included with <link> tags in the HTML head.

If you have plugins that make use of it, html-webpack-plugin should be ordered first before any of the integrated plugins.

Options

You can pass a hash of configuration options to html-webpack-plugin. Allowed values are as follows

Name Type Default Description
title {String} Webpack App The title to use for the generated HTML document
filename {String} 'index.html' The file to write the HTML to. Defaults to index.html. You can specify a subdirectory here too (eg: assets/admin.html)
template {String} `` webpack relative or absolute path to the template. By default it will use src/index.ejs if it exists. Please see the docs for details
templateContent `{string\ Function\ false}`
templateParameters `{Boolean\ Object\ Function}`
inject `{Boolean\ String}` true
publicPath `{String 'auto'}` 'auto'
scriptLoading `{'blocking'\ 'defer'}` 'blocking'
favicon {String} `` Adds the given favicon path to the output HTML
meta {Object} {} Allows to inject meta-tags. E.g. meta: {viewport: 'width=device-width, initial-scale=1, shrink-to-fit=no'}
base `{Object\ String\ false}`
minify `{Boolean\ Object}` true if mode is 'production', otherwise false
hash {Boolean} false If true then append a unique webpack compilation hash to all included scripts and CSS files. This is useful for cache busting
cache {Boolean} true Emit the file only if it was changed
showErrors {Boolean} true 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 `{String\ Function}` auto
excludeChunks {Array.<string>} `` Allows you to skip some chunks (e.g don't add the unit-test chunk)
xhtml {Boolean} false If true render the link tags as self-closing (XHTML compliant)

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

webpack.config.js

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

Generating Multiple HTML Files

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

webpack.config.js

{
  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.

Details of other template loaders are documented here.

plugins: [
  new HtmlWebpackPlugin({
    title: 'Custom template',
    // Load a custom template (lodash by default)
    template: 'index.html'
  })
]

index.html

<!DOCTYPE html>
<html>
  <head>
    <meta 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 specify the html-loader and use .html file as template.

webpack.config.js

module: {
  loaders: [
    { test: /\.hbs$/, loader: "handlebars-loader" }
  ]
},
plugins: [
  new HtmlWebpackPlugin({
    title: 'Custom template using Handlebars',
    template: '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 by default (you can extend them using the templateParameters option):

  • htmlWebpackPlugin: data specific to this plugin

    • 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.
    • htmlWebpackPlugin.tags: the prepared headTags and bodyTags Array to render the <base>, <meta>, <script> and <link> tags. Can be used directly in templates and literals. For example: html <html> <head> <%= htmlWebpackPlugin.tags.headTags %> </head> <body> <%= htmlWebpackPlugin.tags.bodyTags %> </body> </html>
    • htmlWebpackPlugin.files: direct access to the files used during the compilation.
    publicPath: string;
js: string[];
css: string[];
manifest?: string;
favicon?: string;

  • webpackConfig: the webpack configuration that was used for this compilation. This can be used, for example, to get the publicPath (webpackConfig.output.publicPath).

  • compilation: the webpack compilation object. This can be used, for example, to get the contents of processed assets and inline them directly in the page, through compilation.assets[...].source() (see the inline template example).

The template can also be directly inlined directly into the options object.
⚠️ templateContent does not allow to use webpack loaders for your template and will not watch for template file changes

webpack.config.js

new HtmlWebpackPlugin({
  templateContent: `
    <html>
      <body>
        <h1>Hello World</h1>
      </body>
    </html>
  `
})

The templateContent can also access all templateParameters values.
⚠️ templateContent does not allow to use webpack loaders for your template and will not watch for template file changes

webpack.config.js

new HtmlWebpackPlugin({
  inject: false,
  templateContent: ({htmlWebpackPlugin}) => `
    <html>
      <head>
        ${htmlWebpackPlugin.tags.headTags}
      </head>
      <body>
        <h1>Hello World</h1>
        ${htmlWebpackPlugin.tags.bodyTags}
      </body>
    </html>
  `
})

Filtering Chunks

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

webpack.config.js

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

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

webpack.config.js

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

Minification

If the minify option is set to true (the default when webpack's mode is 'production'), the generated HTML will be minified using html-minifier-terser and the following options:

{
  collapseWhitespace: true,
  removeComments: true,
  removeRedundantAttributes: true,
  removeScriptTypeAttributes: true,
  removeStyleLinkTypeAttributes: true,
  useShortDoctype: true
}

To use custom html-minifier options pass an object to minify instead. This object will not be merged with the defaults above.

To disable minification during production mode set the minify option to false.

Meta Tags

If the meta option is set the html-webpack-plugin will inject meta tags.
For the default template the html-webpack-plugin will already provide a default for the viewport meta tag.

Please take a look at this well maintained list of almost all possible meta tags.

name/content meta tags

Most meta tags are configured by setting a name and a content attribute.
To add those use a key/value pair:

webpack.config.js

plugins: [
  new HtmlWebpackPlugin({
      'meta': {
        'viewport': 'width=device-width, initial-scale=1, shrink-to-fit=no',
        // Will generate: <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
        'theme-color': '#4285f4'
        // Will generate: <meta name="theme-color" content="#4285f4">
      }
  })
]

Simulate http response headers

The http-equiv attribute is essentially used to simulate a HTTP response header.
This format is supported using an object notation which allows you to add any attribute:

webpack.config.js

plugins: [
  new HtmlWebpackPlugin({
    'meta': {
      'Content-Security-Policy': { 'http-equiv': 'Content-Security-Policy', 'content': 'default-src https:' },
      // Will generate: <meta http-equiv="Content-Security-Policy" content="default-src https:">
      // Which equals to the following http header: `Content-Security-Policy: default-src https:`
      'set-cookie': { 'http-equiv': 'set-cookie', content: 'name=value; expires=date; path=url' },
      // Will generate: <meta http-equiv="set-cookie" content="value; expires=date; path=url">
      // Which equals to the following http header: `set-cookie: value; expires=date; path=url`
    }
  })
]

Base Tag

When the base option is used, html-webpack-plugin will inject a base tag. By default, a base tag will not be injected.

The following two are identical and will both insert <base href="http://example.com/some/page.html">:

new HtmlWebpackPlugin({
  'base': 'http://example.com/some/page.html'
})

new HtmlWebpackPlugin({
  'base': { 'href': 'http://example.com/some/page.html' }
})

The target can be specified with the corresponding key:

new HtmlWebpackPlugin({
  'base': {
    'href': 'http://example.com/some/page.html',
    'target': '_blank'
  }
})

which will inject the element <base href="http://example.com/some/page.html" target="_blank">.

Long Term Caching

For long term caching add contenthash/templatehash to the filename.

Example:

plugins: [
  new HtmlWebpackPlugin({
    filename: 'index.[contenthash].html'
  })
]

contenthash/templatehash is the hash of the content of the output file.

Optionally, You can configure like [<hashType>:contenthash:<digestType>:<length>]

  • hashType - one of sha1, md5, sha256, sha512 or any other node.js supported hash type
  • digestType - one of hex, base26, base32, base36, base49, base52, base58, base62, base64
  • maxlength - maximum length of the generated hash in chars

Defaults: [md5:contenthash:hex:9999]

Events

To allow other plugins to alter the HTML this plugin executes tapable hooks.

The lib/hooks.js contains all information about which values are passed.

Concept flow uml

beforeAssetTagGeneration hook

    AsyncSeriesWaterfallHook<{
      assets: {
        publicPath: string,
        js: Array<{string}>,
        css: Array<{string}>,
        favicon?: string | undefined,
        manifest?: string | undefined
      },
      outputName: string,
      plugin: HtmlWebpackPlugin
    }>

alterAssetTags hook

    AsyncSeriesWaterfallHook<{
      assetTags: {
        scripts: Array<HtmlTagObject>,
        styles: Array<HtmlTagObject>,
        meta: Array<HtmlTagObject>,
      },
      outputName: string,
      plugin: HtmlWebpackPlugin
    }>

alterAssetTagGroups hook

    AsyncSeriesWaterfallHook<{
      headTags: Array<HtmlTagObject | HtmlTagObject>,
      bodyTags: Array<HtmlTagObject | HtmlTagObject>,
      outputName: string,
      plugin: HtmlWebpackPlugin
    }>

afterTemplateExecution hook

    AsyncSeriesWaterfallHook<{
      html: string,
      headTags: Array<HtmlTagObject | HtmlTagObject>,
      bodyTags: Array<HtmlTagObject | HtmlTagObject>,
      outputName: string,
      plugin: HtmlWebpackPlugin,
    }>

beforeEmit hook

    AsyncSeriesWaterfallHook<{
      html: string,
      outputName: string,
      plugin: HtmlWebpackPlugin,
    }>

afterEmit hook

    AsyncSeriesWaterfallHook<{
      outputName: string,
      plugin: HtmlWebpackPlugin
    }>

Example implementation: webpack-subresource-integrity

plugin.js

// If your plugin is direct dependent to the html webpack plugin:
const HtmlWebpackPlugin = require('html-webpack-plugin');
// If your plugin is using html-webpack-plugin as an optional dependency
// you can use https://github.com/tallesl/node-safe-require instead:
const HtmlWebpackPlugin = require('safe-require')('html-webpack-plugin');

class MyPlugin {
  apply (compiler) {
    compiler.hooks.compilation.tap('MyPlugin', (compilation) => {
      console.log('The compiler is starting a new compilation...')

      // Static Plugin interface |compilation |HOOK NAME | register listener 
      HtmlWebpackPlugin.getHooks(compilation).beforeEmit.tapAsync(
        'MyPlugin', // <-- Set a meaningful name here for stacktraces
        (data, cb) => {
          // Manipulate the content
          data.html += 'The Magic Footer'
          // Tell webpack to move on
          cb(null, data)
        }
      )
    })
  }
}

module.exports = MyPlugin

webpack.config.js

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

Note that the callback must be passed the HtmlWebpackPluginData in order to pass this onto any other plugins listening on the same beforeEmit event

Maintainers

Jan Nicklas
Thomas Sileghem

Backers

Thank you to all our backers!
If you want to support the project as well become a sponsor or a a backer.

Contributors

This project exists thanks to all the people who contribute.

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.