An HTML Optimizer’s Config for html-minifier

Published on Dec 20, 2019 (updated Sep 18, 2024), filed under development, html, performance, optimization (feed). (Share this on Mastodon or Bluesky?)

Jad Joubran asked me about my configuration for html-minifier the other week, and in a hurry I pointed him to the config I had worked out for sum.cumo. In my own projects, however, I work with a different, more ambitious setup. It’s this, which I’m just going to throw over the fence:

collapseBooleanAttributes: true,
collapseInlineTagWhitespace: true,
collapseWhitespace: true,
conservativeCollapse: true,
decodeEntities: true,
includeAutoGeneratedTags: false,
minifyCSS: true,
minifyJS: true,
minifyURLs: true,
preventAttributesEscaping: true,
processConditionalComments: true,
removeAttributeQuotes: true,
removeComments: true,
removeEmptyAttributes: true,
removeOptionalTags: true,
removeRedundantAttributes: true,
removeScriptTypeAttributes: true,
removeStyleLinkTypeAttributes: true,
sortAttributes: true,
sortClassName: true,
trimCustomFragments: true,
useShortDoctype: true

It translates to the following parameters in the command line:

--collapse-boolean-attributes
--collapse-inline-tag-whitespace --collapse-whitespace
--conservative-collapse --decode-entities --minify-css
--minify-js --minify-urls --no-include-auto-generated-tags
--prevent-attributes-escaping --process-conditional-comments
--remove-attribute-quotes --remove-comments --remove-empty-attributes
--remove-optional-tags --remove-redundant-attributes
--remove-script-type-attributes --remove-style-link-type-attributes
--sort-attributes --sort-class-name --trim-custom-fragments
--use-short-doctype

(As you can tell I’m assuming some knowledge about using html-minifier.)

Defensive Optimization

Occasionally I’d use a less aggressive, more “stable” configuration to optimize HTML code. The following setup, for example, I’ve recently used to “polish” the in good parts static files of meiert.com:

collapseBooleanAttributes: true,
decodeEntities: true,
removeOptionalTags: true,
removeRedundantAttributes: true,
removeScriptTypeAttributes: true,
removeStyleLinkTypeAttributes: true

For the command line:

--collapse-boolean-attributes --decode-entities
--remove-optional-tags --remove-redundant-attributes
--remove-script-type-attributes --remove-style-link-type-attributes

Here’s the full command I use in my structure, if that’s useful:

html-minifier --collapse-boolean-attributes --decode-entities
--remove-optional-tags --remove-redundant-attributes
--remove-script-type-attributes --remove-style-link-type-attributes
--file-ext html --input-dir meiert.com/ --output-dir meiert.com/

❧ I work with these setups in a mostly manual fashion because for some projects, like UITest.com or The World’s Highest Website, I intentionally manage everything manually, whereas in others, like HH Kaffee, it’s completely automated. For me this makes for a good mix for honing my skills while not wasting too much time when the code base is rather large.

When it comes to html-minifier, I think Juriy (aka kangax) has done extraordinary work with it. As I said in my optional HTML primer I consider it the best and most important tool for HTML optimization. Use it (while keeping your manual HTML skills sharp)!

Update (September 18, 2024)

html-minifier can take significant time to process, as I’ve been learning in my Eleventy setup for Frontend Dogma. To optimize performance, I’ve fine-tuned my configuration only to use what I really needed or didn’t want to risk missing.

Here’s an updated configuration, with brief individual comments. If performance is not a concern, the config above should be preferable. If it is, you could adopt these settings, but the best course of action would be to go through html-minifier’s settings and cherry-pick according to your project needs.

collapseBooleanAttributes: true, // just in case, but important
collapseWhitespace: true,
decodeEntities: true,
minifyJS: true, // needed in some places
preventAttributesEscaping: true,
removeComments: true,
removeOptionalTags: true, // just in case I missed something
removeRedundantAttributes: true  // just in case I missed something

About Me

I’m Jens (long: Jens Oliver Meiert), and I’m a web developer, manager, and author. I’ve been working as a technical lead and engineering manager for companies you’ve never heard of and companies you use every day, I’m an occasional contributor to web standards (like HTML, CSS, WCAG), and I write and review books for O’Reilly and Frontend Dogma.

I love trying things, not only in web development and engineering management, but also in other areas like philosophy. Here on meiert.com I share some of my experiences and views. (I value you being critical, interpreting charitably, and giving feedback.)