minimizer-webpack-plugin

v5.13.1

Published

7 days ago

Minimizer plugin for webpack

[![npm][npm]][npm-url] [![node][node]][node-url] [![tests][tests]][tests-url] [![cover][cover]][cover-url] [![discussion][discussion]][discussion-url] [![size][size]][size-url]

minimizer-webpack-plugin

This plugin minifies your assets in a webpack build. It ships with several built-in minimizers covering JavaScript, JSON, HTML, CSS, and images — pick one with the minify option and target the right files with test.

JavaScript minimizers:

terser — MinimizerPlugin.terserMinify (default). The same JavaScript-based minifier that webpack uses out of the box; produces small, well-tested output and supports the full set of extractComments modes.
uglify-js — MinimizerPlugin.uglifyJsMinify. ES5-only minifier, useful when you specifically need UglifyJS-compatible output. Requires npm install --save-dev uglify-js.
@swc/core — MinimizerPlugin.swcMinify. A very fast Rust-based JavaScript/TypeScript minifier. Requires npm install --save-dev @swc/core.
esbuild — MinimizerPlugin.esbuildMinify. An extremely fast JS bundler/minifier; legal comments are always preserved (no extractComments support). Requires npm install --save-dev esbuild.

JSON minimizer:

JSON.stringify — MinimizerPlugin.jsonMinify. Built in (no extra dependency); supports space and replacer options.

HTML minimizers:

webpack's own — webpack.html.syntax.htmlMinify. Ships with webpack (>= 5.111.0), so it needs no extra dependency, and it is the one that minifies what a document nests: an inline <style>, every style="", a <script>, an <svg> subtree. See webpack's own minimizers.
html-minifier-terser — MinimizerPlugin.htmlMinifierTerser. JavaScript-based, no native dependency. Requires npm install --save-dev html-minifier-terser.
@swc/html — MinimizerPlugin.swcMinifyHtml (full HTML documents) and MinimizerPlugin.swcMinifyHtmlFragment (HTML fragments, e.g. <template> content). Very fast Rust-based platform for the Web. Requires npm install --save-dev @swc/html.
@minify-html/node — MinimizerPlugin.minifyHtmlNode. A Rust HTML minifier optimised for speed and effectiveness. Requires npm install --save-dev @minify-html/node.

CSS minimizers:

webpack's own — webpack.css.syntax.cssMinify. Ships with webpack (>= 5.111.0), so it needs no extra dependency, and it minifies the CSS a stylesheet or a document nests. See webpack's own minimizers.
cssnano — MinimizerPlugin.cssnanoMinify. Built on top of PostCSS. Requires npm install --save-dev cssnano postcss.
csso — MinimizerPlugin.cssoMinify. A CSS minifier with structural optimisations. Requires npm install --save-dev csso.
clean-css — MinimizerPlugin.cleanCssMinify. A widely-used CSS optimiser. Requires npm install --save-dev clean-css.
esbuild — MinimizerPlugin.esbuildMinifyCss. Very fast CSS minification using esbuild's CSS loader. Requires npm install --save-dev esbuild.
lightningcss — MinimizerPlugin.lightningCssMinify. A Rust-based CSS parser, transformer, and minifier. Requires npm install --save-dev lightningcss.
@swc/css — MinimizerPlugin.swcMinifyCss. A very fast Rust-based CSS minifier. Requires npm install --save-dev @swc/css.

Image minimizers:

sharp — MinimizerPlugin.sharpMinify. Re-encodes an image as the format its name already claims (avif, gif, heif, jp2, jpeg, png, tiff, webp), and can resize, rotate, flip, grayscale, blur or sharpen on the way — from the options or from the asset's own name. Requires npm install --save-dev sharp.
svgo — MinimizerPlugin.svgoMinify. Minifies SVG, including an asset/inline SVG that no test can match. Requires npm install --save-dev svgo.
imagemin — MinimizerPlugin.imageminMinify. Runs the imagemin plugins you name. Requires npm install --save-dev imagemin plus each plugin. Pair it with MinimizerPlugin.imageminGenerate under generate when a plugin converts the format, since only that can rename the asset.
@napi-rs/image — MinimizerPlugin.napiRsImageMinify. Rust codecs with no system dependency; recompresses png losslessly with oxipng and jpeg with mozjpeg, and can resize, turn, mirror, grayscale, invert or blur on the way — from the options or from the asset's own name. Requires npm install --save-dev @napi-rs/image.

These only minify — they never change an image's format or name; see Images.

Transport encodings:

zlib and anything shaped like it — MinimizerPlugin.compress. Compresses an asset so a server can serve it under Content-Encoding. Takes algorithm — a zlib function's name (gzip, brotliCompress, deflate, zstdCompress, …) or one of your own — and compressionOptions for it, and needs no extra dependency. Give it to minify to compress an asset in place, or to generate as an asset generator to write the compressed file beside the original; either way it puts itself after the minimizers, through a getStage of its own.

All of the non-default minimizers are declared as optional peer dependencies — install only the ones you actually use. One plugin instance covers several languages at once: give minify an array and each minimizer is offered only the assets its own filter accepts, so JS, CSS, HTML and JSON share a single worker pool (see Examples).

Getting Started

Webpack v5 comes with the latest minimizer-webpack-plugin out of the box. If you are using Webpack v5 or above and wish to customize the options, you will still need to install minimizer-webpack-plugin. Using Webpack v4, you have to install terser-webpack-plugin v4 (minimizer-webpack-plugin is only published for Webpack v5+).

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

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

yarn add -D minimizer-webpack-plugin

pnpm add -D minimizer-webpack-plugin

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

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

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

Finally, run webpack using the method you normally use (e.g., via CLI or an npm script).

Note about source maps

Works only with source-map, inline-source-map, hidden-source-map and nosources-source-map values for the devtool option.

Why?

eval wraps modules in eval("string") and the minimizer does not handle strings.
cheap has no column information and the minimizer generates only a single line, which leaves only a single mapping.

Using supported devtool values enable source map generation.

Options

`test`

Type:

type test = string | RegExp | (string | RegExp)[];

Default: /\.m?js(\?.*)?$/i

Test to match files against.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        test: /\.js(\?.*)?$/i,
      }),
    ],
  },
};

`include`

Type:

type include = string | RegExp | (string | RegExp)[];

Default: undefined

Files to include.

webpack.config.js

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

`exclude`

Type:

type exclude = string | RegExp | (string | RegExp)[];

Default: undefined

Files to exclude.

webpack.config.js

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

`parallel`

Type:

type parallel = boolean | number;

Default: true

Use multi-process parallel running to improve the build speed.

Default number of concurrent runs: os.cpus().length - 1 or os.availableParallelism() - 1 (if this function is supported).

Note
Parallelization can speedup your build significantly and is therefore highly recommended.

Warning
If you use Circle CI or any other environment that doesn't provide the real available count of CPUs then you need to explicitly set up the number of CPUs to avoid Error: Call retries were exceeded (see #143, #202).

`boolean`

Enable/disable multi-process parallel running.

webpack.config.js

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

`number`

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

webpack.config.js

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

`minify`

Type:

type minifyFn = (
  input: Record<string, string | Buffer>,
  sourceMap: import("@jridgewell/trace-mapping").SourceMapInput | undefined,
  minifyOptions: {
    module?: boolean | undefined;
    ecma?: import("terser").ECMA | undefined;
  },
  extractComments:
    | boolean
    | "all"
    | "some"
    | RegExp
    | ((
        astNode: any,
        comment: {
          value: string;
          type: "comment1" | "comment2" | "comment3" | "comment4";
          pos: number;
          line: number;
          col: number;
        },
      ) => boolean)
    | {
        condition?:
          | boolean
          | "all"
          | "some"
          | RegExp
          | ((
              astNode: any,
              comment: {
                value: string;
                type: "comment1" | "comment2" | "comment3" | "comment4";
                pos: number;
                line: number;
                col: number;
              },
            ) => boolean)
          | undefined;
        filename?: string | ((fileData: any) => string) | undefined;
        banner?:
          string | boolean | ((commentsFile: string) => string) | undefined;
      }
    | undefined,
) => Promise<{
  code: string;
  map?: import("@jridgewell/trace-mapping").SourceMapInput | undefined;
  errors?: (string | Error)[] | undefined;
  warnings?: (string | Error)[] | undefined;
  extractedComments?: string[] | undefined;
}>;

interface minimizer {
  implementation: minifyFn;
  options?: Record<string, any>;
}

type minify = minifyFn | (minifyFn | minimizer)[] | minimizer;
// An empty array is nothing to minify.

Default: MinimizerPlugin.terserMinify

Which minimizer runs, and the options it runs with. By default the plugin uses terser; overriding it is also how you test an unpublished version or a fork. The default stands whether or not a generate was configured too, and so does test's: the JavaScript minifier and the names it reads are what this plugin is.

Nothing minifying is an empty array rather than a missing value, for an instance whose whole job is its generate:

new MinimizerPlugin({
  test: /.*/,
  minify: [],
  generate: {
    implementation: MinimizerPlugin.compress,
    options: { algorithm: "gzip" },
    type: "asset",
    filename: "[path][base].gz",
  },
});

false is not accepted. A list with nothing in it needs no guard at any of the places that run the minimizers — each simply does nothing — while a second kind of value does.

Warning
Always use require inside minify function when parallel option enabled.

`object`

The form to prefer: the minimizer and its own options in one place.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: MinimizerPlugin.swcMinify,
          options: { mangle: false },
        },
      }),
    ],
  },
};

options reaches the minify function as its third argument, and what it takes is that minimizer's own: Terser's minify options for the default one, and the tables in webpack's own minimizers for cssMinify and htmlMinify.

implementation may also name a module path rather than hold the function itself — a string, or { path, export } for a named export, the way sass-loader takes its implementation. A worker then requires the minimizer, which is what the default terser is named by; one written as a function is handed over as source for the worker to rebuild with new Function:

new MinimizerPlugin({
  minify: {
    // Or the string on its own, where the module exports the function itself.
    implementation: {
      path: require.resolve("./my-minifier"),
      export: "minify",
    },
  },
});

The saving is per task, so it needs every minimizer of that task to be nameable: one written as a function anywhere in the list leaves the whole task on the source path, since that function has no other way across. So does a function anywhere in what the task carries — an extractComments callback, or a minimizer's own options holding one — because a required minimizer is handed the payload as it is, and a structured clone throws on a function.

filter(name, info) states which assets this minimizer is offered — return false to decline one, and anything else (undefined included) to accept. It answers for a filter property on the minimizer function itself, which is what the built-ins carry, so setting it here is how you narrow one of them without wrapping it.

new MinimizerPlugin({
  minify: {
    implementation: MinimizerPlugin.sharpMinify,
    options: { encodeOptions: { jpeg: { quality: 80 } } },
    filter: (name) => !name.includes("do-not-touch"),
  },
});

Two keys are filled in before a minimizer sees them, and only when options does not set them itself: ecma, from output.environment, and module, from the asset's own javascriptModule info or its .mjs / .cjs extension. Setting either yourself wins, including module: false.

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: MinimizerPlugin.terserMinify,
          options: {
            ecma: undefined,
            parse: {},
            compress: {},
            mangle: true, // Note `mangle.properties` is `false` by default.
            module: false,
            // Deprecated
            output: null,
            format: null,
            toplevel: false,
            nameCache: null,
            ie8: false,
            keep_classnames: undefined,
            keep_fnames: false,
            safari10: false,
          },
        },
      }),
    ],
  },
};

`array`

Several minimizers are an array of objects, rather than one object holding two lists that have to line up. Each asset is dispatched to the minimizers whose filter accepts it, and when more than one accepts the same asset the output of each is fed to the next (the chain semantic). Warnings, errors and extracted comments from all of them are merged.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: [
          {
            implementation: MinimizerPlugin.terserMinify,
            options: { mangle: false },
          },
          { implementation: MinimizerPlugin.swcMinify },
        ],
      }),
    ],
  },
};

Each entry carries its own filter as well as its own options, which is how the same minimizer runs twice over different assets:

new MinimizerPlugin({
  test: /\.(jpe?g|png)$/i,
  minify: [
    {
      implementation: MinimizerPlugin.sharpMinify,
      options: { encodeOptions: { jpeg: { quality: 60 } } },
      filter: (name) => name.includes("thumb"),
    },
    {
      implementation: MinimizerPlugin.sharpMinify,
      options: { encodeOptions: { jpeg: { quality: 90 } } },
      filter: (name) => !name.includes("thumb"),
    },
  ],
});

This is also what lets one plugin instance and one worker pool handle every asset type: each built-in ships with a filter matching its natural extension, so JS, CSS, HTML and JSON need no second instance. test still defaults to JS only, so widen it to let the other assets reach the dispatcher:

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        test: /\.(?:[cm]?js|css|html?|json)(\?.*)?$/i,
        minify: [
          { implementation: MinimizerPlugin.terserMinify },
          { implementation: MinimizerPlugin.cssnanoMinify },
          { implementation: MinimizerPlugin.htmlMinifierTerser },
          { implementation: MinimizerPlugin.jsonMinify },
        ],
      }),
    ],
  },
};

Pair it with webpack's own cssMinify and htmlMinify and the source a document or a stylesheet nests inside itself is minified too — see Embedded source.

`function`

A bare function is shorthand for an object with no options. A custom one says what it can do through properties on the function itself — each optional, and each answering a question the plugin would otherwise have to guess at.

webpack.config.js

// Can be async
const minify = (input, sourceMap, minimizerOptions, extractsComments) => {
  // Whatever the `minify` option's `options` holds reaches the third argument
  // You can use `minimizerOptions.myCustomOption`

  // Custom logic for extract comments
  const { map, code } = require("uglify-module") // Or require('./path/to/uglify-module')
    .minify(input, {/* Your options for minification */});

  return { map, code, warnings: [], errors: [], extractedComments: [] };
};

// Used to regenerate `fullhash`/`chunkhash` between different implementation
// Example: you fix a bug in custom minimizer/custom function, but unfortunately webpack doesn't know about it, so you will get the same fullhash/chunkhash
// to avoid this you can provide version of your custom minimizer
// You don't need if you use only `contenthash`
minify.getMinimizerVersion = () => {
  let packageJson;

  try {
    packageJson = require("uglify-module/package.json");
  } catch (error) {
    // Ignore
  }

  return packageJson && packageJson.version;
};

// Restrict the minimizer to the assets it can actually handle. The plugin
// skips assets for which `filter` returns `false` and (when an array of
// minimizers is used) dispatches each asset only to the minimizers that
// accept it. Returning `undefined` is treated as accept.
minify.filter = (name) => /\.[cm]?js(\?.*)?$/i.test(name);

// The languages this minimizer minifies. Source a module embeds in another
// language carries no filename, so `filter` cannot dispatch it and this does
// — a function without it is never handed any.
minify.getTypes = () => ["javascript"];

// Declare this when the minimizer reads the asset's bytes rather than its
// text — an image minimizer. Its `input` values then arrive as a `Buffer` and
// its `code` may be one. Only applied when every minimizer an asset is
// dispatched to declares it, since one that does not could not read the bytes.
minify.supportsBinary = () => true;

// Declare this when the minimizer has to run somewhere other than where
// minification does — it is handed the `Compilation` class so it can name a
// stage rather than a number. Each minimizer runs where it asks, chaining
// through the asset a later one reads back; one asking for nothing runs where
// minifying belongs.
minify.getStage = (compilation) =>
  compilation.PROCESS_ASSETS_STAGE_OPTIMIZE_TRANSFER;

// The name this function's work goes under: the asset it writes is marked
// with it in the asset info, and stats print it. A minimizer declaring
// nothing minified the asset, so `minimized`; a generator declaring nothing
// wrote a new file, so `generated`. It is also what is not run twice — an
// asset already marked with every name a function writes is declined, which
// is how one minified by a child compilation is left alone.
minify.getAssetFlag = () => "compressed";

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: minify,
          options: { myCustomOption: true },
        },
      }),
    ],
  },
};

A minifier that nests other languages inside what it prints — a document with an inline <style>, a stylesheet with a data: URL — hands each nested body out instead of minifying it itself. It declares which languages it can offer, and the plugin passes renderEmbeddedSource in its options when something else claims one of them:

async function myHtmlMinify(input, sourceMap, minimizerOptions) {
  const [[, code]] = Object.entries(input);
  const { renderEmbeddedSource } = minimizerOptions;

  // Absent when nothing configured claims a language this minifier offers
  const minifyStyle = async (css) => {
    const result = renderEmbeddedSource
      ? await renderEmbeddedSource(css, { type: "css" })
      : undefined;

    // Declining leaves the body exactly as it was written
    return result && typeof result.code === "string" ? result.code : css;
  };

  return { code: await print(code, minifyStyle) };
}

// The languages this minifier can hand out, given the options it will run with
myHtmlMinify.getEmbeddedTypes = (minimizerOptions) => ["css", "javascript"];

renderEmbeddedSource(source, { type, as }) answers { code?, warnings?, errors? } or undefined, and recurses — a body that nests something of its own is reached too. as says which production of type the body is; a style="" is "block-contents" rather than a whole stylesheet. Embedded source has the whole picture.

`minimizerOptions`

Note
Deprecated, and to be removed in the next major release. Give a minimizer its options in minify instead, which keeps one minimizer's configuration in one place. It keeps working, and setting the options for one minimizer in both places is an error.

Type:

type minimizerOptions = Record<string, any> | Record<string, any>[];

Default: Terser's

Options for the active minimizer, given away from it. With an array of minimizers it may be an array too — each element goes to the minimizer at the same index — or one object every minimizer is handed. It is still the only way to configure the default minimizer without naming it:

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

terserOptions is a deprecated alias of it — passing either is equivalent, and minimizerOptions wins if both are set.

`generate`

Type:

type generateFn = (
  input: Record<string, string | Buffer>,
  sourceMap: undefined,
  generatorOptions: Record<string, any>,
) => Promise<{
  code: string | Buffer;
  filename?: string;
  errors?: (Error | string)[];
  warnings?: (Error | string)[];
}>;

interface generator {
  implementation: generateFn;
  options?: Record<string, any>;
  type?: "import" | "asset";
  filename?: string | ((pathData: any) => string);
  filter?: (name: string) => boolean;
  deleteOriginalAssets?: boolean | ((name: string) => boolean);
  threshold?: number;
  minRatio?: number;
  relatedName?: string | false;
}

type generate =
  | generateFn
  | generateFn[]
  | generator
  | Record<string, generateFn | generateFn[] | generator>;

Default: undefined

Rewrites a module's own bytes as it is built, rather than an asset after the build. That is the one point at which a re-encoding can also rename — return a filename and the asset is emitted under it, with every reference in the bundle following. minify cannot: an asset's name is decided during code generation, so renaming there would leave the bundle pointing at a URL nothing emits.

test, include and exclude select which modules it sees, matched against the module's resource — query and all, so ?as=webp is matchable. A generator runs in the webpack process, since modules build before the worker pool is up, and its answer is cached under the bytes plus the generator and its options.

Two generators ship with the plugin, and they differ in who picks the format. sharpGenerate is told: it takes the target from the request's ?as= or, failing that, from an options.encodeOptions naming exactly one format, and reports an error when neither says which format to write. imageminGenerate is not: its plugins decide, so it reads the format back off the bytes they produced and renames to match, leaving an asset its plugins did not convert under the name it had.

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  module: {
    rules: [
      {
        test: /\.(jpe?g|png)$/i,
        type: "asset/resource",
        // The query has to survive into the name, or two formats of one image
        // collide.
        generator: { filename: "[name][ext][query]" },
      },
    ],
  },
  plugins: [
    new MinimizerPlugin({
      test: /\.(jpe?g|png)$/i,
      generate: MinimizerPlugin.sharpGenerate,
    }),
  ],
};

// `image.jpg` is emitted as `image.webp`, and this import points at it.
import webp from "./image.jpg?as=webp";

Written as an object, generate names its generators, and an asset picks one by name with ?as=:

new MinimizerPlugin({
  test: /\.(jpe?g|png)$/i,
  generate: {
    webp: {
      implementation: MinimizerPlugin.sharpGenerate,
      options: { encodeOptions: { webp: { quality: 90 } } },
    },
    avif: {
      implementation: MinimizerPlugin.sharpGenerate,
      options: { encodeOptions: { avif: { quality: 50 } } },
    },
  },
});

// And `./image.jpg?as=avif` for the other one.
import webp from "./image.jpg?as=webp";

A module naming no preset is left alone, so the same build can import an image unconverted. One naming a preset nothing defines is an error rather than a silent decline, since the name it asked for is what the bundle would point at.

A generator can also be written as an object — on its own, or under a name — which is where its own options live and what lets it read what was emitted instead of a module as it builds:

new MinimizerPlugin({
  test: /\.(jpe?g|png)$/i,
  generate: {
    webp: {
      implementation: MinimizerPlugin.sharpGenerate,
      options: { encodeOptions: { webp: {} } },
      type: "asset",
      // Optional, a template or a function answering with one. Without it the
      // generator's own name for the result is used, which for `sharpGenerate`
      // is the original with its extension replaced.
      filename: "[path][name].webp",
      // Optional. Narrows what this generator reads, on top of `test`.
      filter: (name) => !name.includes("icons/"),
      // Optional, `false` by default: the asset it read stays where it is.
      // Written as a function it is asked per asset.
      deleteOriginalAssets: false,
      // Optional. Skips an asset this small, before the generator is asked.
      threshold: 10240,
      // Optional. Drops the result unless it is this much smaller than what
      // it read, as `generated size / original size`.
      minRatio: 0.8,
      // Optional. The key the new file is recorded under in the original's
      // `related` info, which is how a server asked for one finds the other.
      relatedName: "webp",
    },
  },
});

type decides which of the two things a generator does, and they are not interchangeable — they read different input, at different points in the build:

"import" is the only point at which a rename can reach the bundle: the asset is named while its module is built, so every reference follows it. The import that asked for the conversion gets the converted file.

new MinimizerPlugin({
  test: /\.(jpe?g|png)$/i,
  generate: { webp: { implementation: MinimizerPlugin.sharpGenerate } },
});

import url from "./photo.jpg?as=webp"; // url is "photo.webp"

const same = new URL("./photo.jpg?as=webp", import.meta.url); // photo.webp

.hero {
  background: url("./photo.jpg?as=webp"); /* photo.webp */
}

photo.webp    the jpg became this

Those are one asset module between them, so an import, a new URL() and a CSS url() all follow the rename. An asset inlined as a data URI carries no file name, and takes the media type of what it became — data:image/webp;….

"asset" leaves what it read alone and writes another file next to it, so both survive — the <picture> case, where the .webp goes in a srcset you write yourself and the .jpg stays as the fallback. Nothing imports the new file, so ?as= cannot reach it and its preset name selects nothing; the name is only how you address its options. An asset already generated is never generated from again.

new MinimizerPlugin({
  test: /\.(jpe?g|png)$/i,
  generate: {
    webp: { implementation: MinimizerPlugin.sharpGenerate, type: "asset" },
  },
});

import url from "./photo.jpg"; // url is "photo.jpg", unchanged

photo.jpg     still there, unless `deleteOriginalAssets`
photo.webp    generated beside it

filename, filter, deleteOriginalAssets, threshold, minRatio and relatedName describe a file being written beside another, so they belong to "asset" and setting one on an "import" generator is an error rather than a field that quietly does nothing.

Three of them decide whether the new file is worth having. threshold skips an asset too small to bother with, before the generator is asked at all. minRatio drops a result that is not enough smaller than what it read, since a file that saves nothing still costs a request. relatedName records the new file under that key in the original's related info — which is how a server asked for the original finds it — and declines an asset already carrying that key.

A file written under the original's own name has replaced it, so there is nothing beside it to delete and nothing for relatedName to point at; a generator doing that re-encodes an asset in place.

Deleting takes the original file and nothing else. webpack deletes whatever an asset's related names along with it, so a source map, or the file a second generator wrote beside the same original, would go too; the original goes alone instead. Where the generated file took the original's own name there is nothing left to delete, and relatedName is not recorded when the asset that would carry it is being deleted.

A generated file inherits nothing from the one it was read from: what the original's info says about its hashes, its module and where its source came from is true of that file and not of this one. The exception is immutable, and only where filename still derives from the original's name — [name], [base] or [file] — since that is what carried the hash the promise rests on.

When a generator runs is not among them, because it is not the config's to say: the implementation declares it through a getStage of its own, the way it declares everything else about itself — see minify. Compressing has to read the bytes a user downloads, so MinimizerPlugin.compress asks for PROCESS_ASSETS_STAGE_OPTIMIZE_TRANSFER and runs after every minimizer has had its say; one that asks for nothing runs where minifying does. The name its work goes under is the implementation's too, through the same kind of helper: a generator declaring nothing wrote a new file, so generated, while compress says compressed, another encoding of the bytes being no smaller a version of them. Whatever the name, stats print it and the generator declines a file already carrying it, so nothing reads its own output back.

MinimizerPlugin.compress ships with the plugin and is written against that. algorithm says which compression to run — a zlib function's name, or one of your own taking (input, options, callback) — and compressionOptions is what that algorithm is run with, the way terserMinify takes terser's own options. Here it is as an asset generator, which writes the compressed file beside the one it read, so both survive and the URL says which is which:

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        test: /\.(js|css|html|svg)$/i,
        generate: {
          gzip: {
            implementation: MinimizerPlugin.compress,
            options: { algorithm: "gzip" },
            type: "asset",
            filename: "[path][base].gz",
          },
          brotli: {
            implementation: MinimizerPlugin.compress,
            options: {
              algorithm: "brotliCompress",
              compressionOptions: { params: {} },
            },
            type: "asset",
            filename: "[path][base].br",
          },
        },
      }),
    ],
  },
};

Minifying and compressing are then one plugin over one pass of filtering and one cache, and the ordering they need — compress what minification produced — is what stage states rather than what applying two plugins in the right order happens to give. Each algorithm is run at its own maximum by default (zlib's best level, brotli's best quality); name compressionOptions to say otherwise.

Compressing with minifying, and without

The example above does both: minify defaults to terser, so the bundle is minified and the compressed files are written from what minification produced. That is the shape to want — one pass of filtering, one cache, and stage ordering the two — and it needs nothing said about minify at all:

new MinimizerPlugin({
  test: /\.(js|css|html|svg)$/i,
  generate: {
    implementation: MinimizerPlugin.compress,
    options: { algorithm: "gzip" },
    type: "asset",
    filename: "[path][base].gz",
  },
});

Compressing only — an instance that must not touch what it reads — says so with an empty list of minimizers. test is then yours to state too, since the .js default belongs to minifying:

new MinimizerPlugin({
  test: /.*/,
  minify: [],
  generate: {
    implementation: MinimizerPlugin.compress,
    options: { algorithm: "gzip" },
    type: "asset",
    filename: "[path][base].gz",
  },
});

Nothing is minified, no asset is marked minimized, and the bundle keeps the name it would have had without this plugin — an instance that rewrites nothing salts no hash.

It is an ordinary minimizer too, so minify takes it the way it takes terserMinify or swcMinify. There it compresses the asset in place rather than beside it — the shape for a server that says what the encoding is through Content-Encoding while the URL stays as it was:

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        test: /\.js$/i,
        minify: MinimizerPlugin.compress,
        minimizerOptions: { algorithm: "gzip" },
      }),
    ],
  },
};

An array runs its minimizers in order, each one reading what the last produced, so minifying and then compressing in place is one entry after another — and each states its own options. Each runs at the stage it asks for — terser before the hash is taken, compress after — so [contenthash] still names what minification produced:

new MinimizerPlugin({
  test: /\.js$/i,
  minify: [
    { implementation: MinimizerPlugin.terserMinify },
    {
      implementation: MinimizerPlugin.compress,
      options: { algorithm: "brotliCompress" },
    },
  ],
});

ecma is filled in from output.environment unless a generator's options set it, the same way it is for a minimizer's — see minify.

filename is a webpack filename template resolved against the asset read, so [path], [name], [base], [ext] and [query] are available; content hashes are not, because the name derives from one the original already carries.

In watch mode the rename is carried on the module rather than reapplied each build, so a rebuild that does not touch the image keeps pointing at the generated name without running the generator again. Changing the image does run it again, since its answer is cached under the bytes.

The same holds across runs under cache.type: "filesystem", where a module is restored from the pack rather than rebuilt. That restored result is the generator's, so changing a generator or its options has to invalidate the pack, and the plugin adds their identity to cache.version so it does. This needs the plugin to be in the config — plugins or optimization.minimizer — since webpack builds the cache while it applies them; a plugin applied by hand after webpack() returns is too late to reach it, and a changed generator would then be ignored until the cache directory is removed.

Note
Note
generatorOptions is kept as a deprecated way of giving a generator its options — one object for one generator, an array positionally matching an array of them, or keyed by name where generate names its generators. Prefer a generator's own options. Setting both for one generator is an error, and a key naming no generator is an error rather than silently doing nothing.

Note
An "import" generator needs a webpack whose NormalModule processResult hook can be awaited (5.111 or newer), since that is where a rename has to happen. On an older webpack the plugin reports an error rather than silently generating nothing. An "asset" generator does not use that hook and works on any supported webpack.

`extractComments`

Type:

type extractComments =
  | boolean
  | string
  | RegExp
  | ((
      astNode: any,
      comment: {
        value: string;
        type: "comment1" | "comment2" | "comment3" | "comment4";
        pos: number;
        line: number;
        col: number;
      },
    ) => boolean)
  | {
      condition?:
        | boolean
        | "all"
        | "some"
        | RegExp
        | ((
            astNode: any,
            comment: {
              value: string;
              type: "comment1" | "comment2" | "comment3" | "comment4";
              pos: number;
              line: number;
              col: number;
            },
          ) => boolean)
        | undefined;
      filename?: string | ((fileData: any) => string) | undefined;
      banner?:
        string | boolean | ((commentsFile: string) => string) | undefined;
    };

Default: true

Whether comments shall be extracted to a separate file, (see details).

By default, extract only comments using /^\**!|@preserve|@license|@cc_on/i RegExp condition and remove remaining comments.

If the original file is named foo.js, then the comments will be stored to foo.js.LICENSE.txt.

A minimizer's options.format.comments specifies whether the comment will be preserved - i.e., it is possible to preserve some comments (e.g. annotations) while extracting others, or even preserve comments that have already been extracted.

`boolean`

Enable/disable extracting comments.

webpack.config.js

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

`string`

Extract all or some (use the /^\**!|@preserve|@license|@cc_on/i RegExp) comments.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        extractComments: "all",
      }),
    ],
  },
};

`RegExp`

All comments that match the given expression will be extracted to a separate file.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        extractComments: /@extract/i,
      }),
    ],
  },
};

`function`

All comments that match the given expression will be extracted to a separate file.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        extractComments: (astNode, comment) => {
          if (/@extract/i.test(comment.value)) {
            return true;
          }

          return false;
        },
      }),
    ],
  },
};

`object`

Allows you to customize condition for extracting comments, and specify the extracted file name and banner.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        extractComments: {
          condition: /^\**!|@preserve|@license|@cc_on/i,
          filename: (fileData) =>
            // The "fileData" argument contains object with "filename", "basename", "query" and "hash"
            `${fileData.filename}.LICENSE.txt${fileData.query}`,
          banner: (licenseFile) =>
            `License information can be found in ${licenseFile}`,
        },
      }),
    ],
  },
};

`condition`

Type:

type condition =
  | boolean
  | "all"
  | "some"
  | RegExp
  | ((
      astNode: any,
      comment: {
        value: string;
        type: "comment1" | "comment2" | "comment3" | "comment4";
        pos: number;
        line: number;
        col: number;
      },
    ) => boolean)
  | undefined;

The condition that determines which comments should be extracted.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        extractComments: {
          condition: "some",
          filename: (fileData) =>
            // The "fileData" argument contains object with "filename", "basename", "query" and "hash"
            `${fileData.filename}.LICENSE.txt${fileData.query}`,
          banner: (licenseFile) =>
            `License information can be found in ${licenseFile}`,
        },
      }),
    ],
  },
};

`filename`

Type:

type filename = string | ((fileData: any) => string) | undefined;

Default: [file].LICENSE.txt[query]

Available placeholders: [file], [query] and [filebase] ([base] for webpack 5).

The file where the extracted comments will be stored.

Default is to append the suffix .LICENSE.txt to the original filename.

Warning
We highly recommend using the .txt extension. Using .js/.cjs/.mjs extensions may conflict with existing assets, which leads to broken code.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        extractComments: {
          condition: /^\**!|@preserve|@license|@cc_on/i,
          filename: "extracted-comments.js",
          banner: (licenseFile) =>
            `License information can be found in ${licenseFile}`,
        },
      }),
    ],
  },
};

`banner`

Type:

type banner = string | boolean | ((commentsFile: string) => string) | undefined;

Default: /*! For license information please see ${commentsFile} */

The banner text that points to the extracted file and will be added at the top of the original file.

It can be false (no banner), a String, or a function<(string) -> String> that will be called with the filename where the extracted comments have been stored.

The banner will be wrapped in a comment: /*! … */ by default, or whatever the minify function's formatBanner helper returns. An HTML minimizer needs one, since a /*! line is text in a document:

minify.formatBanner = (banner) => `<!-- ${banner} -->`;

The banner goes at the top of the asset; a getBannerPosition helper returning "end" appends it instead, which keeps a document's doctype first:

minify.getBannerPosition = () => "end";

The source of both helpers is part of the cache key and the [chunkhash], but not the values they close over: a helper whose output depends on such a value must make getMinimizerVersion change with it, or a rebuild reuses the earlier banner from the cache.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        extractComments: {
          condition: true,
          filename: (fileData) =>
            // The "fileData" argument contains object with "filename", "basename", "query" and "hash"
            `${fileData.filename}.LICENSE.txt${fileData.query}`,
          banner: (commentsFile) =>
            `My custom banner about license information ${commentsFile}`,
        },
      }),
    ],
  },
};

Embedded source

Source written in one language that reaches the bundle inside another is minified too, which no asset carries and an asset-level minimizer therefore never sees. It needs no option (webpack >= 5.110.0; older versions reach only what an asset nests inside itself).

Such source has no filename, so test / include / exclude and each minimizer's filter — all of which match filenames — cannot dispatch it. It is dispatched by the language it is written in, which every minify function states for itself:

myCssMinifier.getTypes = () => ["css"];

webpack's own cssMinify and htmlMinify declare css and html, and are the two that hand out what they nest. The built-ins declare javascript (terserMinify, uglifyJsMinify, swcMinify, esbuildMinify), css (cssnanoMinify, cssoMinify, cleanCssMinify, esbuildMinifyCss, lightningCssMinify, swcMinifyCss), html (htmlMinifierTerser, swcMinifyHtml, swcMinifyHtmlFragment, minifyHtmlNode) and json (jsonMinify). A language no configured minimizer claims — svg out of the box — is emitted exactly as it was written, and a custom minify function without getTypes is never handed embedded source at all.

What this reaches:

CSS and HTML a module embeds in a JavaScript string literal (every exportType but link).
The text an asset/source module embeds, and the payload an asset/inline module encodes — the payload before it is encoded, so the encoding covers what came back. A language written as text only: an inline svg is offered, an inline png or jpeg is not, so a raster image that becomes a data: URI is minified by generate rather than here.
What a document or a stylesheet nests inside itself: an inline <style>, every style="", a <script> holding JavaScript or JSON, an <svg> subtree, the document an <iframe srcdoc> holds, and the payload of a url() data: URL. This is how an inline <script> is minified by terser at all.

A style="" arrives as css with as: "block-contents" — the same word module.parser.css.as uses. It holds a block's contents rather than a whole stylesheet, so a minifier claiming css is handed one either way and as says which it is. Ignore it at your peril: parsing a declaration list as a stylesheet finds no rule and returns nothing.

A <script type="module"> arrives the same way, as javascript with as: "module": JavaScript has two productions too, and a module script is one wherever it sits. The built-in JavaScript minimizers read it as their own module option, so the engine is never handed the word itself; a minify function of your own claiming javascript is handed it and decides. Ignore it at your peril: a module script read as a classic one is a syntax error the moment it holds a top-level await.

An event handler attribute — onclick="" — arrives as javascript with as: "event-handler": its value is a function body, the production the return cancelling an event is written in. No JavaScript engine here parses one on its own, so each built-in minimizer minifies the function that body belongs to and answers with the body back out of it. A minify function of your own is handed the body as written and reads it however its engine can.

The nested case needs a minifier that can hand its nested bodies out, which it also states for itself — webpack's cssMinify and htmlMinify do:

// The languages this minifier can offer, given the options it will run with.
myHtmlMinifier.getEmbeddedTypes = (minimizerOptions) => ["css", "javascript"];

The option is passed only when the two declarations meet: if nothing configured claims a language this minifier could offer, it is never handed one, and minification is exactly what it always was. When it is, the nested bodies are reached in the same parse that prints — the minifier leaves a marker where each one goes and the answers are put in their place, so nothing is parsed twice.

Note
Source a module embeds in JavaScript is minified during code generation, before the worker pool is up, so parallel does not apply to it. What an asset nests inside itself is minified in the pool with the asset.

Examples

Preserve Comments

Extract all legal comments (i.e. /^\**!|@preserve|@license|@cc_on/i) and preserve /@license/i comments.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: MinimizerPlugin.terserMinify,
          options: { format: { comments: /@license/i } },
        },
        extractComments: true,
      }),
    ],
  },
};

Remove Comments

If you want to build without comments, use this config:

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: MinimizerPlugin.terserMinify,
          options: { format: { comments: false } },
        },
        extractComments: false,
      }),
    ],
  },
};

`uglify-js`

UglifyJS is a JavaScript parser, minifier, compressor and beautifier toolkit.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: MinimizerPlugin.uglifyJsMinify,
          // `options` will be passed to `uglify-js`
          // Link to options - https://github.com/mishoo/UglifyJS#minify-options
          options: {},
        },
      }),
    ],
  },
};

`swc`

swc is a super-fast compiler written in Rust, producing widely supported JavaScript from modern standards and TypeScript.

Warning
extractComments is supported with @swc/core >= 1.15.30. Only serializable extract conditions are supported: booleans, "some", "all", string patterns, RegExp values without flags, or object conditions that resolve to those forms. Function conditions and flagged regular expressions are not supported.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: MinimizerPlugin.swcMinify,
          // `options` will be passed to `swc` (`@swc/core`)
          // Link to options - https://swc.rs/docs/config-js-minify
          options: {},
        },
      }),
    ],
  },
};

`esbuild`

esbuild is an extremely fast JavaScript bundler and minifier.

Warning
The extractComments option is not supported, and all legal comments (i.e. copyright, licenses and etc) will be preserved.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new MinimizerPlugin({
        minify: {
          implementation: MinimizerPlugin.esbuildMinify,
          // `options` will be passed to `esbuild`
          // Link to options - https://esbuild.github.io/api/#minify
          // Note: the `minify` options is true by default (and override other `minify*` options), so if you want to disable the `minifyIdentifiers` option (or other `minify*` options) please use:
          // options: {
          //   minify: false,
          //   minifyWhitespace: true,
          //   minifyIdentifiers: false,
          //   minifySyntax: true,
          // },
          options: {},
        },
      }),
    ],
  },
};

JSON

Uses JSON.stringify() to minify your JSON files during the build process.

webpack.config.js

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      // Keeps original terser plugin to minify JS files
      "...",
      // Will minify JSON files (they can come from copy-webpack-plugin or when you are using asset modules)
      new MinimizerPlugin({
        test: /\.json$/,
        minify: {
          implementation: MinimizerPlugin.jsonMinify,
          // We are supporting `space` and `replacer` options, you can set them below
          options: {},
        },
      }),
    ],
  },
};

HTML

The plugin can minify HTML assets too. Pick one of the bundled HTML minimizers and set test to match your HTML files.

Available HTML minimizers:

webpack.html.syntax.htmlMinify — webpack's own, shipped with webpack itself, so it needs no extra dependency. The one that can minify what a document nests — an inline <style>, a <script>, an <svg>. See webpack's own minimizers.
MinimizerPlugin.htmlMinifierTerser — uses html-minifier-terser.
MinimizerPlugin.swcMinifyHtml — uses @swc/html for full HTML documents (with doctype and <html>/<head>/<body> tags).
MinimizerPlugin.swcMinifyHtmlFragment — uses @swc/html for HTML fragments (e.g. content inside <template></template> or partial HTML strings).
MinimizerPlugin.minifyHtmlNode — uses @minify-html/node.

The HTML minimizers are optional peer dependencies — install only the one you actually use:

npm install --save-dev html-minifier-terser
# or
npm install --save-dev @swc/html
# or
npm install --save-dev @minify-html/node

Note
HTML assets typically come from plugins like copy-webpack-plugin, html-webpack-plugin, or webpack's asset modules.

Note
Whitespace handling differs between tools (defaults):
@swc/html — removes/collapses whitespace only in safe places (around html/body, inside <head>, between <meta>/<script>/<link> etc.).
html-minifier-terser — always collapses multiple whitespaces to a single space (never removes entirely); configurable via its options.
@minify-html/node — see its whitespace docs.

`html-minifier-terser`

html-minifier-terser is a JavaScript-based HTML minifier with no native dependency.

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      // Keeps the default Terser plugin for JS files
      "...",
      new MinimizerPlugin({
        test: /\.html(\?.*)?$/i,
        minify: {
          implementation: MinimizerPlugin.htmlMinifierTerser,
          // Options - https://github.com/terser/html-minifier-terser#options-quick-reference
          options: {
            collapseWhitespace: true,
            removeComments: true,
          },
        },
      }),
    ],
  },
};

`@swc/html` — HTML documents

Use swcMinifyHtml for complete HTML documents (i.e. with a doctype and <html>/<head>/<body> tags).

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      "...",
      new MinimizerPlugin({
        test: /\.html(\?.*)?$/i,
        minify: {
          implementation: MinimizerPlugin.swcMinifyHtml,
          // Options - https://github.com/swc-project/bindings/blob/main/packages/html/index.ts
          options: {},
        },
      }),
    ],
  },
};

`@swc/html` — HTML fragments

Use swcMinifyHtmlFragment for partial HTML — for example, content of <template></template> tags or HTML strings that get injected into another document.

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      "...",
      new MinimizerPlugin({
        test: /\.template\.html$/i,
        minify: {
          implementation: MinimizerPlugin.swcMinifyHtmlFragment,
          // Options - https://github.com/swc-project/bindings/blob/main/packages/html/index.ts
          options: {},
        },
      }),
    ],
  },
};

Note
The difference between swcMinifyHtml and swcMinifyHtmlFragment is the error reporting — invalid or broken syntax is reported at build time.

`@minify-html/node`

@minify-html/node is a Rust HTML minifier.

webpack.config.js

const Minimizer = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      "...",
      new Minimizer({
        test: /\.html(\?.*)?$/i,
        minify: {
          implementation: Minimizer.minifyHtmlNode,
          // Options - https://github.com/wilsonzlin/minify-html#minification
          options: {},
        },
      }),
    ],
  },
};

You can also stack multiple MinimizerPlugin instances to compress different files with different minify functions in the same build (e.g. JS with terserMinify, HTML with htmlMinifierTerser, JSON with jsonMinify).

CSS

The plugin can minify CSS assets too. Pick one of the bundled CSS minimizers and set test to match your CSS files.

Available CSS minimizers:

webpack.css.syntax.cssMinify — webpack's own, shipped with webpack itself, so it needs no extra dependency. The one that can minify the CSS a document nests. See webpack's own minimizers.
MinimizerPlugin.cssnanoMinify — uses cssnano (via postcss).
MinimizerPlugin.cssoMinify — uses csso.
MinimizerPlugin.cleanCssMinify — uses clean-css.
MinimizerPlugin.esbuildMinifyCss — uses esbuild with the CSS loader.
MinimizerPlugin.lightningCssMinify — uses lightningcss.
MinimizerPlugin.swcMinifyCss — uses @swc/css.

The CSS minimizers are optional peer dependencies — install only the ones you actually use:

npm install --save-dev cssnano postcss
# or
npm install --save-dev csso
# or
npm install --save-dev clean-css
# or
npm install --save-dev esbuild
# or
npm install --save-dev lightningcss
# or
npm install --save-dev @swc/css

Note
CSS assets typically come from plugins like mini-css-extract-plugin or webpack's asset modules.

`cssnano`

cssnano runs as a PostCSS plugin.

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      // Keeps the default Terser plugin for JS files
      "...",
      new MinimizerPlugin({
        test: /\.css(\?.*)?$/i,
        minify: {
          implementation: MinimizerPlugin.cssnanoMinify,
          // Options - https://cssnano.github.io/cssnano/docs/config-file/
          options: {
            preset: "default",
          },
        },
      }),
    ],
  },
};

`csso`

csso is a CSS minifier with structural optimisations.

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      "...",
      new MinimizerPlugin({
        test: /\.css(\?.*)?$/i,
        minify: {
          implementation: MinimizerPlugin.cssoMinify,
          // Options - https://github.com/css/csso#minifysource-options
          options: {},
        },
      }),
    ],
  },
};

`clean-css`

clean-css is a widely-used CSS optimiser.

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      "...",
      new MinimizerPlugin({
        test: /\.css(\?.*)?$/i,
        minify: {
          implementation: MinimizerPlugin.cleanCssMinify,
          // Options - https://github.com/clean-css/clean-css#constructor-options
          options: {},
        },
      }),
    ],
  },
};

`esbuild`

esbuild ships with a fast CSS minifier (used via its CSS loader).

webpack.config.js

const MinimizerPlugin = require("minimizer-webpack-plugin");

module.exports = {
  optimization: {
    minimize: true,

Published

Vulnerabilities

Links

Maintainers

Keywords

Readme

minimizer-webpack-plugin

Getting Started

Note about source maps

Options

test

include

exclude

parallel

boolean

number

minify

object

array

function

minimizerOptions

generate

Compressing with minifying, and without

extractComments

boolean

string

RegExp

function

object

condition

filename

banner

Embedded source

Examples

Preserve Comments

Remove Comments

uglify-js

swc

esbuild

JSON

HTML

html-minifier-terser

@swc/html — HTML documents

@swc/html — HTML fragments

@minify-html/node

CSS

cssnano

csso

clean-css

esbuild

`test`

`include`

`exclude`

`parallel`

`boolean`

`number`

`minify`

`object`

`array`

`function`

`minimizerOptions`

`generate`

`extractComments`

`boolean`

`string`

`RegExp`

`function`

`object`

`condition`

`filename`

`banner`

`uglify-js`

`swc`

`esbuild`

`html-minifier-terser`

`@swc/html` — HTML documents

`@swc/html` — HTML fragments

`@minify-html/node`

`cssnano`

`csso`

`clean-css`

`esbuild`