postcss-html

What is postcss-html?

The postcss-html npm package is a tool that allows PostCSS to be used with HTML, including HTML-like syntaxes such as XML, XHTML, and HTML with inline styles. It enables developers to process styles within `<style>` tags or inline `style` attributes using PostCSS plugins.

What are postcss-html's main functionalities?

Processing inline styles

This feature allows processing of inline styles within HTML. The code sample demonstrates how to use postcss-html to process a string containing HTML with a `<style>` tag.

const postcssHtml = require('postcss-html');
const result = postcssHtml.process('<style>h1 { color: red; }</style>', { /* options */ }).then(result => {
  console.log(result.html);
});

Processing styles in HTML-like files

This feature processes styles within HTML-like files. The code sample shows how to read an HTML file, process it with postcss-html, and then write the processed HTML to a new file.

const postcssHtml = require('postcss-html');
const fs = require('fs');

fs.readFile('index.html', (err, html) => {
  if (err) throw err;
  postcssHtml.process(html, { /* options */ }).then(result => {
    fs.writeFile('index-processed.html', result.html, (err) => {
      if (err) throw err;
      console.log('The file has been saved!');
    });
  });
});

Other packages similar to postcss-html

postcss-scss

The postcss-scss package is a syntax for PostCSS that allows you to work with SCSS (Sassy CSS) directly, without converting it to CSS first. It is similar to postcss-html in that it extends PostCSS's capabilities to non-standard CSS syntaxes, but it focuses on SCSS rather than HTML.

postcss-jsx

postcss-jsx is an npm package that enables PostCSS to parse and transform CSS within JSX files. It is similar to postcss-html as it extends PostCSS to handle CSS within a different context (JSX instead of HTML), allowing for linting and other transformations within JavaScript frameworks like React.

stylelint

stylelint is a powerful, modern linter that helps you avoid errors and enforce conventions in your styles. It is similar to postcss-html in that it can be used to lint styles within HTML files, but it is primarily a standalone tool rather than a PostCSS plugin.

README

PostCSS HTML Syntax

PostCSS Syntax for parsing HTML

Getting Started

First thing's first, install the module:

npm install postcss-html --save-dev

If you want support SCSS/SASS/LESS/SugarSS syntax in HTML, you need to install the corresponding module.

• SCSS: PostCSS-SCSS
• SASS: PostCSS-SASS
• LESS: PostCSS-LESS
• SugarSS: SugarSS

Use Cases

Style Transformations

The main use case of this plugin is to apply PostCSS transformations directly to HTML source code. For example, if you ship a theme written in style tag in HTML and need Autoprefixer to add the appropriate vendor prefixes to it; or you need to lint style source in HTML with a plugin such as Stylelint.

var syntax = require('postcss-html');
postcss(plugins).process(html, { syntax: syntax }).then(function (result) {
    result.content // HTML with transformations
});

custom Syntax for styles

Using map object configuration

var syntax = require('postcss-html');
postcss(plugins).process(html, {
	syntax: syntax({
		css: require('postcss'),
		less: require('postcss-less'),
		scss: require('postcss-scss'),
	})
}).then(function (result) {
    result.content // HTML with transformations
});

Using callback function configuration

var syntax = require('postcss-html');
postcss(plugins).process(html, {
	syntax: syntax((opts, lang) => {
		if (lang) {
			// `lang`: language of style tag in html.
			// style tag in HTML file
			if (lang === 'less') {
				// `<style type="text/less">`
				return require('postcss-scss')
			}
		} else if(opts.from) {
			// `opts`: See http://api.postcss.org/global.html#processOptions
			if (/\.less$/.test(opts.from)) {
				// `*.less` file
				return require('postcss-less')
			}
		}
	})
}).then(function (result) {
    result.content // HTML with transformations
});