rehype plugins to minify HTML.
This GitHub repository is a monorepo that contains a couple utilities, ±30 plugins, and a preset with good and safe default, to minify HTML:
<!doctype html>
<html lang="en-GB">
<head>
<meta charset="utf-8">
<meta http-equiv="content-language" content="en-US">
<script src="index.js" type="text/javascript" language="javascript">
alert(true);
</script>
<link rel="stylesheet" href="index.css" type="text/css">
<title>Foo & bar</title>
</head>
<body>
<h1 class="foo foo">bar bar</h1>
<p id="alfred" id="alfred"> <strong>foo</strong> <em>bar</em> </p>
<button type="BUTTON" onclick="javascript:return false">Alpha</button>
</body>
</html><!doctypehtml><html lang=en><meta charset=utf8><script src=index.js></script><link href=index.css rel=stylesheet><title>Foo & bar</title><h1 class=foo>bar bar</h1><p id=alfred><strong>foo</strong> <em>bar</em></p><button onclick=return!1 type=button>Alpha</button>This project is useful when you want to improve the size of HTML documents. It’s particularly useful when you’re already using rehype (and remark?) to process HTML.
Presets are combinations of plugins. One preset is maintained here:
rehype-preset-minify— preset to minify and mangle HTML
The following plugins maintained here are included in the above preset.
rehype-minify-attribute-whitespacerehype-minify-css-stylerehype-minify-enumerated-attributerehype-minify-event-handlerrehype-minify-javascript-scriptrehype-minify-javascript-urlrehype-minify-json-scriptrehype-minify-languagerehype-minify-media-attributerehype-minify-meta-colorrehype-minify-meta-contentrehype-minify-style-attributerehype-minify-whitespacerehype-normalize-attribute-value-caserehype-remove-commentsrehype-remove-duplicate-attribute-valuesrehype-remove-empty-attributerehype-remove-external-script-contentrehype-remove-meta-http-equivrehype-remove-script-type-javascriptrehype-remove-style-type-cssrehype-sort-attribute-valuesrehype-sort-attributes
The following plugins are not included in the preset as they are potentially dangerous, can make sites slower in certain cases, or need extra configuration. Read their readmes before using:
rehype-concat-css-stylerehype-concat-javascriptrehype-css-to-toprehype-javascript-to-bottomrehype-minify-urlrehype-prevent-favicon-request
Also: pass allowDangerousCharacters to rehype-stringify
if you trust your content.
Here’s a benchmark comparing the results from html-minifier
and rehype-minify.
To summarize: differences are negligible, in fact, minifying HTML doesn’t matter
much.
What does matter is using good compressions, such as gzip.
Note: html-minifier sometimes crashes, such as on amazon.
| name | raw | gzip | ||||
|---|---|---|---|---|---|---|
| original | rehype-minify | html-minifier | original | rehype-minify | html-minifier | |
| amazon | 567.85KB | 5.71% | 💥 | 128.65KB | 5.07% | 💥 |
| bbc | 531.54KB | 4.70% | 4.58% | 58.09KB | 1.85% | 1.96% |
| bootstrap | 33.96KB | 22.36% | 22.82% | 8.12KB | 5.17% | 5.36% |
| compat-table | 8.67MB | 16.34% | 16.74% | 275.06KB | 8.26% | 10.06% |
| ecmascript | 6.62MB | 10.86% | 11.56% | 789.66KB | 6.39% | 6.60% |
| eloquent | 80.08KB | 6.43% | 6.45% | 19.13KB | 1.25% | 1.26% |
| github | 233.14KB | 13.39% | 14.51% | 38.86KB | 7.48% | 7.91% |
| 253.98KB | 3.13% | 3.20% | 80.56KB | 3.64% | 3.63% | |
| guardian | 765.54KB | 6.75% | 8.71% | 112.21KB | 3.96% | 4.38% |
| html | 12.72MB | 3.15% | 3.19% | 1.85MB | 5.49% | 5.58% |
| 120.77KB | 32.29% | 32.34% | 14.4KB | 13.99% | 13.91% | |
| microsoft | 174.26KB | 22.44% | 34.12% | 26.45KB | 12.96% | 15.45% |
| nbc | 1.64MB | 5.94% | 6.28% | 221.08KB | 1.86% | 1.92% |
| npm | 27.98KB | 3.03% | 2.61% | 8.28KB | 2.22% | 2.01% |
| nytimes | 822.38KB | 11.80% | 11.80% | 137.47KB | 2.71% | 2.72% |
| slack | 205.45KB | 4.76% | 4.55% | 49.63KB | 2.06% | 1.98% |
| stackoverflow | 169.8KB | 18.64% | 19.10% | 45.4KB | 6.42% | 6.67% |
| vice | 337.93KB | 3.48% | 3.22% | 92.58KB | 2.61% | 2.52% |
| wikipedia | 768.18KB | 6.08% | 6.76% | 144KB | 1.58% | 1.77% |
| total | 34.63MB | 31.9MB | 31.83MB | 4.05MB | 3.85MB | 3.85MB |
Huge differences in results are suspicious and may point to bugs.
💥 — Crash.
Use of rehype-preset-minify is safe by default if the tree is already safe.
As rehype works on HTML and improper use of HTML can open you up to a
cross-site scripting (XSS) attack, use of rehype can also be unsafe.
Use rehype-sanitize to make the tree safe.
To further optimize the result disregarding security, use the extra plugins
listed above and pass allowDangerousCharacters to
rehype-stringify.
rehype-format— format HTML
See contributing.md in rehypejs/.github for ways
to get started.
See support.md for ways to get help.
This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.
