Speed and effectiveness of Node.js version compared to [html-minfier](https://github.com/kangax/html-minifier) and [minimize](https://github.com/Swaagie/minimize). See [bench](./bench) folder for more details.
<imgwidth="435"alt="Chart showing speed of HTML minifiers"src="https://wilsonl.in/hyperbuild/bench/0.0.39/average-speeds.png"><imgwidth="435"alt="Chart showing effectiveness of HTML minifiers"src="https://wilsonl.in/hyperbuild/bench/0.0.39/average-sizes.png">
hyperbuild is [on npm](https://www.npmjs.com/package/hyperbuild), available as a [Node.js native module](https://neon-bindings.com/), and supports Node.js versions 8 and higher.
hyperbuild is [on PyPI](https://pypi.org/project/hyperbuild), available as a [native module](https://github.com/PyO3/pyo3), and supports CPython (the default Python interpreter) versions 3.5 and higher.
hyperbuild is published on [RubyGems](https://rubygems.org/gems/hyperbuild), available as a [native module](https://github.com/danielpclark/rutie) for macOS and Linux, and supports Ruby versions 2.5 and higher.
There are three whitespace minification methods. When processing text content, hyperbuild chooses which ones to use depending on the containing element.
> **Applies to:** any element except [whitespace sensitive](./src/spec/tag/whitespace.rs), [content](src/spec/tag/whitespace.rs), [content-first](./src/spec/tag/whitespace.rs), and [formatting](./src/spec/tag/whitespace.rs) elements.
hyperbuild recognises elements based on one of a few ways it assumes they are used. By making these assumptions, it can apply optimal whitespace minification strategies.
Formatting elements are usually inline elements that wrap around part of some text in a content element, so its whitespace isn't trimmed as they're probably part of the content.
Content elements usually represent a contiguous and complete unit of content such as a paragraph. As such, whitespace is significant but sequences of them are most likely due to formatting.
These elements should only contain other elements and no text. This makes it possible to remove whole whitespace, which is useful when using `display: inline-block` so that whitespace between elements (e.g. indentation) does not alter layout and styling.
These elements are usually like content elements but are occasionally used like a layout element with one child. Whole whitespace is not removed as it might contain content, but this is OK for using as layout as there is only one child and whitespace is trimmed.
`type` attributes on `script` tags with a value equaling a [JavaScript MIME type](https://mimesniff.spec.whatwg.org/#javascript-mime-type) are removed.
If an attribute value is empty after any processing, everything but the name is completely removed (i.e. no `=`), as an empty attribute is implicitly [the same](https://html.spec.whatwg.org/multipage/syntax.html#attributes-2) as an attribute with an empty string value.
Numeric entities that do not refer to a valid [Unicode Scalar Value](https://www.unicode.org/glossary/#unicode_scalar_value) are replaced with the [replacement character](https://en.wikipedia.org/wiki/Specials_(Unicode_block)#Replacement_character).
If an entity is unintentionally formed after decoding, the leading ampersand is encoded, e.g. `&amp;` becomes `&amp;`. This is done as `&` is equal to or shorter than all other entity representations of characters part of an entity (`[&#a-zA-Z0-9;]`), and there is no other conflicting entity name that starts with `amp`.
Bangs, [processing instructions](https://en.wikipedia.org/wiki/Processing_Instruction), and empty elements are not removed as it is assumed there is a special reason for their declaration.
For example, this means that it's not an error to have self-closing tags, declare multiple `<body>` elements, use incorrect attribute names and values, or write something like `<br>alert('');</br>`
Tag names are case sensitive. For example, this means that `P` won't be recognised as a content element, `bR` won't be considered as a void tag, and the contents of `Script` won't be parsed as JavaScript.
Tags must not be [omitted](https://html.spec.whatwg.org/multipage/syntax.html#syntax-tag-omission). Void tags must not have a separate closing tag e.g. `</input>`.
They are interpreted as characters representing their decoded value. This means that `	` is considered a whitespace character and could be minified.
Malformed entities are interpreted literally as a sequence of characters.
If a named entity is an invalid reference as per the [specification](https://html.spec.whatwg.org/multipage/named-characters.html#named-character-references), it is considered malformed.
Numeric character references that do not reference a valid [Unicode Scalar Value](https://www.unicode.org/glossary/#unicode_scalar_value) are considered malformed.
Special handling of some attributes require case sensitive names and values. For example, `CLASS` won't be recognised as an attribute to minify, and `type="Text/JavaScript"` on a `<script>` will not be removed.
If hyperbuild did something unexpected, misunderstood some syntax, or incorrectly kept/removed some code, [raise an issue](https://github.com/wilsonzlin/hyperbuild/issues) with some relevant code that can be used to reproduce and investigate the issue.
