htmlnano

Modular HTML minifier, built on top of the PostHTML. Inspired by cssnano.

Benchmarks

Latest benchmarks: https://github.com/maltsev/html-minifiers-benchmark (updated daily).

Documentation

https://htmlnano.netlify.app

Usage

npm install htmlnano

const htmlnano = require('htmlnano');
const options = {
    removeEmptyAttributes: false, // Disable the module "removeEmptyAttributes"
    collapseWhitespace: 'conservative' // Pass options to the module "collapseWhitespace"
};
// posthtml, posthtml-render, and posthtml-parse options
const postHtmlOptions = {
    sync: true, // https://github.com/posthtml/posthtml#usage
    lowerCaseTags: true, // https://github.com/posthtml/posthtml-parser#options
    quoteAllAttributes: false, // https://github.com/posthtml/posthtml-render#options
};

htmlnano
    // "preset" arg might be skipped (see "Presets" section below for more info)
    // "postHtmlOptions" arg might be skipped
    .process(html, options, preset, postHtmlOptions)
    .then(function (result) {
        // result.html is minified
    })
    .catch(function (err) {
        console.error(err);
    });

More usage examples (PostHTML, Gulp, Webpack): https://htmlnano.netlify.app/next/usage

Change Log

All notable changes to this project will be documented in this file. This project adheres to Semantic Versioning.

2.1.5 - 2025-09-19

Fixed

• Broken CommonJS import (#373)

2.1.4 - 2025-09-05

Fixed

• Broken import (#342)

2.1.3 - 2025-09-03

Changed

• Migrate to TypeScript (#336)
• Remove docs/ from the npm package.

2.1.2 - 2025-04-30

Added

• skipInternalWarnings flag to avoid console.warn output #293

Fixed

• Use Node.js sort instead of timsort #328

2.1.1 - 2024-04-28

Fixed

• Downlevel-revealed closing comment being deleted in safe mode #278

2.1.0 - 2023-10-19

Added

• Convert htmlnano to ES Modules #260

Fixed

• Collapse white spaces according to specs #257

2.0.4 - 2023-04-15

Fixed

• Should not minify <script> and <style> with SRI #220
• Should not merge <style> or <script> with SRI #220
• Should not minify json with SRI #220

2.0.3 - 2022-11-13

Added

• Minify function for HtmlMinimizerWebpackPlugin

Fixed

• collapseWhitespace: handle textNode when comment is preserved #184
• minifyUrls: srcset & javascript: url #185
• Correct missing value default usage
• collapseBooleanAttributes: empty string attributes
• Guard type of attributes' value #195
• Do not choke on svg error #197

Changed

• Minify based on invalid value default
• Avoid hardcoding preset keys

2.0.2 - 2022-04-06

Fixed

• JSON-LD crash #182

2.0.1 - 2022-04-04

This version contains a critical bug #182. Don't use it.

Changed

• Speed improvements #127
• Fix <img sizes> #180

2.0.0 - 2022-01-12

The major version has to be released because of vulnerability in PostCSS (see #165)

Changed

• Support optional dependencies #168 (minifyUrl, minifyJs, removeUnusedCss, minifyCss). This might be a breaking change for you. Check the docs: https://github.com/posthtml/htmlnano/pull/168/files
• Disable mergeScripts & mergeStyles in the safe preset #170.

1.1.1 - 2021-09-19

This version fixes fatal errors introduced in 1.1.0.

1.1.0 - 2021-09-19

This version contains fatal errors. Please use 1.1.1 instead.

Added

• Collapse missing value default attribute in removeRedundantAttributes #158.
• New normalizeAttributeValues module to normalize casing of attribute values #163.
• Custom matcher for removeComments #156.

Changed

• Remove more empty attributes in removeEmptyAttributes #161.
• Enhance collapse whitespace in collapseWhitespace #145.
• minifyJs and minifyUrls enhancement #159.
• Enhance attribute collapse whitespace in collapseAttributeWhitespace #157.

1.0.1 - 2021-09-11

Added

• Support of @novaatwarren/uncss fork #154

Changed

• SVGO plugins configuration #153

1.0.0 - 2021-04-17

After more than 4 years of development, it's time to release a stable 1.0.0 version 🎉

It doesn't contain anything new from the previous 0.2.9 release. We just did a major upgrade of two dependencies: PurgeCSS and SVGO, which changed their config format. Thus we have to do a major release of htmlnano.

You can safely upgrade to `htmlnano@1.0.0if you don't pass any config tominifySvgorremoveUnusedCss` (while used with PurgeCSS) modules. Otherwise, you have to adapt the config according to the new PurgeCSS@3 and SVGO@2 config format.

0.2.9 - 2021-04-11

Added

• minifyConditionalComment support <html> #125.
• Minify JS within <script type="module"> #135.

Fixed

• collapseWhitespaces around comment #120.
• handle CDATA inside script correctly #122.
• Minify SVG correctly #129.

Changed

• Upgrade to terser@5 (JS minification).

0.2.8 - 2020-11-15

Added

• removeOptionalTags #110.
• sortAttributes #113.
• source[src] and srcset support to minifyUrls #117.
• minifyConditionalComments #119.

Changed

• Sort by frequency sortAttributesWithLists #111.
• Strip more spaces in collapseWhitespace #112.
• Remove loading="eager" from <img> and <iframe> #114.
• Remove redundant type from <script> #114.
• Strip whitespaces between textnode and element #116.

0.2.7 - 2020-10-17

Added

• More aggressive whitespace removal option #90.
• Cloudflare SSE support to removeComments #94.
• Improve compression ratio by sorting attribute values #95.
• New minifyUrls module #98.
• New removeAttributeQuotes module #104.
• Remove type=text/css for link[rel=stylesheet] #102.
• Collapse crossorigin attributes #107.
• Exclude excerpt comment for common CMS #108.

Fixed

• Keep JS inside SVG wrapped in //<![CDATA[ //]] #88.

0.2.6 - 2020-07-15

Added

• Let PostHTML options to be passed.

Fixed

• <script> tags merging without content.

0.2.5 - 2019-11-09

Added

• Option to remove unused CSS using PurgeCSS #84.

Fixed

• Keep the order of inline and external JS #80.

0.2.4 - 2019-07-11

Fixed

• Remove crossorigin from boolean attribute #78, #79.
• Disable SVGO plugin convertShapeToPath in safe preset #76.

0.2.3 - 2019-02-14

Fixed

• Keep <g> in SVG by default #71.

0.2.2 - 2019-01-03

Added

• removeUnusedCss module #36.

Fixed

• Bug when tag === false #66.
• Add crossorigin to boolean attributes #67.

0.2.1 - 2018-12-01

Fixed

• Disable JS minifying on AMP pages #65.

0.2.0 - 2018-09-14

Breaking changes

• The API of minifyCss module has been changed since cssnano has been updated to version 4, which has a different API. Check the following resources for more info:
  • htmlnano docs
  • cssnano docs
  • Diff of commit 979f2c with the changes of related docs.

Added

• Add presets #64.
• Add collapseAttributeWhitespace module for collapsing spaces in list-like attributes #25.
• Add deduplicateAttributeValues module for de-duplicating values in list-like attributes #39.
• Better support for AMP pages #59.
• Collapse whitespaces between top-level tags #24.

Changed

• Improve whitespace normalization using normalize-html-whitespace #21.

Fixed

• Don't collapse visible="false" attributes in A-Frame pages #62.

0.1.10 - 2018-08-03

Fixed

• Merging <script> tags without leading ; #55.

0.1.9 - 2018-04-29

Fixed

• Default minification options safety #50.

0.1.8 - 2018-04-17

Fixed

• ES6+ minification #48.

0.1.7 - 2018-03-13

Fixed

• Update dependencies which also fixes the SVG minification bug #47.

0.1.6 - 2017-06-27

Fixed

• "Not a function" error #42.

0.1.5 - 2016-04-24

Added

• Minify SVG #28.
• Merge <script> #19.

Changed

• Remove redundant type="submit" from <button> #31.

Fixed

• Windows build #30.

0.1.4 - 2016-02-16

Added

• Minify JSON.
• Merge multiple <style> into one.
• Collapse boolean attributes.
• Remove redundant attributes.
• HTML minifiers benchmark #22.

Changed

• Expand list of JSON-like mime types #20.

0.1.3 - 2016-02-09

Fixed

• Don't alter HTML comments inside not relevant modules #17.

0.1.2 - 2016-02-07

Fixed

• Don't remove conditional comments in safe mode #13.
• Downgrade: String.startsWith -> String.search.

0.1.1 - 2016-01-31

Added

• Minify CSS inside <style> tags and style attributes.
• Minify JS inside <script> tags and on* attributes.

Changed

• Remove attributes that contains only white spaces.