HtmlMinimizerWebpackPlugin

This plugin can use 2 tools to optimize and minify your HTML:

• html-minifier-terser (by default) - JavaScript-based HTML minifier.
• swc - very fast Rust-based platform for the Web.

Getting Started

To begin, you'll need to install html-minimizer-webpack-plugin:

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

or

yarn add -D html-minimizer-webpack-plugin

or

pnpm add -D html-minimizer-webpack-plugin

Additional step: If you want to use @swc/html you need to install it:

npm install @swc/html --save-dev

or

yarn add -D @swc/html

or

pnpm add -D @swc/html

Then add the plugin to your webpack configuration. For example:

webpack.config.js

const HtmlMinimizerPlugin = require("html-minimizer-webpack-plugin");
const CopyPlugin = require("copy-webpack-plugin");

module.exports = {
  module: {
    rules: [
      {
        test: /\.html$/i,
        type: "asset/resource",
      },
    ],
  },
  plugins: [
    new CopyPlugin({
      patterns: [
        {
          context: path.resolve(__dirname, "dist"),
          from: "./src/*.html",
        },
      ],
    }),
  ],
  optimization: {
    minimize: true,
    minimizer: [
      // For webpack@5 you can use the `...` syntax to extend existing minimizers (i.e. `terser-webpack-plugin`), uncomment the next line
      // `...`

      // For `html-minifier-terser`:
      //
      new HtmlMinimizerPlugin(),

      // For `@swc/html`:
      //
      // new HtmlMinimizerPlugin({
      //   minify: HtmlMinimizerPlugin.swcMinify,
      //   minimizerOptions: {}
      // })
    ],
  },
};

This will enable HTML optimization only in production mode. If you want to run it also in development set the optimization.minimize option to true.

And run webpack via your preferred method.

Note

Removing and collapsing spaces in the tools differ (by default).

• html-minifier-terser - always collapse multiple whitespaces to 1 space (never remove it entirely), but you can change it using options
• @swc/html - remove and collapse whitespaces only in safe places (for example - around html and body elements, inside the head element and between metadata elements - <meta>/script/link/etc.)

Options

• test
• include
• exclude
• parallel
• minify
• minimizerOptions

test

Type:

type test = string | RegExp | Array<string | RegExp>;

Default: /\.html(\?.*)?$/i

Test to match files against.

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        test: /\.foo\.html/i,
      }),
    ],
  },
};

include

Type:

type include = string | RegExp | Array<string | RegExp>;

Default: undefined

Files to include.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        include: /\/includes/,
      }),
    ],
  },
};

exclude

Type:

type exclude = string | RegExp | Array<string | RegExp>;

Default: undefined

Files to exclude.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        exclude: /\/excludes/,
      }),
    ],
  },
};

parallel

Type:

type parallel = undefined | boolean | number;

Default: true

Use multi-process parallel running to improve the build speed. Default number of concurrent runs: os.cpus().length - 1.

Note

Parallelization can speed up your build significantly and is therefore highly recommended.

boolean

Enable/disable multi-process parallel running.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        parallel: true,
      }),
    ],
  },
};

number

Enable multi-process parallel running and set number of concurrent runs.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        parallel: 4,
      }),
    ],
  },
};

minify

Type:

type minify =
  | ((
      data: { [file: string]: string },
      minimizerOptions: {
        [key: string]: any;
      }
    ) => {
      code: string;
      errors?: unknown[] | undefined;
      warnings?: unknown[] | undefined;
    })
  | ((
      data: { [file: string]: string },
      minimizerOptions: {
        [key: string]: any;
      }
    ) => {
      code: string;
      errors?: unknown[] | undefined;
      warnings?: unknown[] | undefined;
    })[];

Default: HtmlMinimizerPlugin.htmlMinifierTerser

Allows you to override default minify function. By default, plugin uses html-minifier-terser package.

We currently support:

• HtmlMinimizerPlugin.htmlMinifierTerser
• HtmlMinimizerPlugin.swcMinify

Useful for using and testing unpublished versions or forks.

Warning

Always use require inside minify function when parallel option enabled.

function

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        minimizerOptions: {
          collapseWhitespace: true,
        },
        minify: (data, minimizerOptions) => {
          const htmlMinifier = require("html-minifier-terser");
          const [[filename, input]] = Object.entries(data);

          return {
            code: htmlMinifier.minify(input, minimizerOptions),
            warnings: [],
            errors: [],
          };
        },
      }),
    ],
  },
};

array

If an array of functions is passed to the minify option, the minimizerOptions can be an array or an object. If minimizerOptions is array, the function index in the minify array corresponds to the options object with the same index in the minimizerOptions array. If you use minimizerOptions like object, all minify function accept it.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        minimizerOptions: [
          // Options for the first function (HtmlMinimizerPlugin.htmlMinifierTerser)
          {
            collapseWhitespace: true,
          },
          // Options for the second function
          {},
        ],
        minify: [
          HtmlMinimizerPlugin.htmlMinifierTerser,
          (data, minimizerOptions) => {
            const [[filename, input]] = Object.entries(data);
            // To do something
            return {
              code: `optimised code`,
              warnings: [],
              errors: [],
            };
          },
        ],
      }),
    ],
  },
};

minimizerOptions

Type:

type minimizerOptions =
  | {
      [key: string]: any;
    }
  | Array<{
      [key: string]: any;
    }>;

Default: { caseSensitive: true, collapseWhitespace: true, conservativeCollapse: true, keepClosingSlash: true, minifyCSS: true, minifyJS: true, removeComments: true, removeScriptTypeAttributes: true, removeStyleLinkTypeAttributes: true, }

Html-minifier-terser optimizations options.

object

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        minimizerOptions: {
          collapseWhitespace: false,
        },
      }),
    ],
  },
};

array

The function index in the minify array corresponds to the options object with the same index in the minimizerOptions array. If you use minimizerOptions like object, all minify function accept it.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        minimizerOptions: [
          // Options for the first function (HtmlMinimizerPlugin.htmlMinifierTerser)
          {
            collapseWhitespace: true,
          },
          // Options for the second function
          {},
        ],
        minify: [
          HtmlMinimizerPlugin.htmlMinifierTerser,
          (data, minimizerOptions) => {
            const [[filename, input]] = Object.entries(data);
            // To do something
            return {
              code: `optimised code`,
              warnings: [],
              errors: [],
            };
          },
        ],
      }),
    ],
  },
};

Examples

swc/html

const HtmlMinimizerPlugin = require("html-minimizer-webpack-plugin");
const CopyPlugin = require("copy-webpack-plugin");

module.exports = {
  module: {
    rules: [
      {
        test: /\.html$/i,
        type: "asset/resource",
      },
    ],
  },
  plugins: [
    new CopyPlugin({
      patterns: [
        {
          context: path.resolve(__dirname, "dist"),
          from: "./src/*.html",
        },
      ],
    }),
  ],
  optimization: {
    minimize: true,
    minimizer: [
      new HtmlMinimizerPlugin({
        minify: HtmlMinimizerPlugin.swcMinify,
        minimizerOptions: {
          // Options
        },
      }),
    ],
  },
};

Contributing

Please take a moment to read our contributing guidelines if you haven't yet done so.

CONTRIBUTING

License

MIT