stylehacks

What is stylehacks?

The stylehacks npm package is designed to detect and remove hacks from CSS files. These hacks are often used to target specific browsers with CSS rules that wouldn't be valid or necessary in a standards-compliant browser. By identifying and removing these hacks, stylehacks helps in cleaning up CSS files, making them more maintainable and potentially reducing file size.

What are stylehacks's main functionalities?

Detecting CSS hacks

This feature allows the detection and automatic removal of CSS hacks. The code sample demonstrates how to use stylehacks with PostCSS to process a CSS string that contains a hack (`_color: red`), which is targeted at old versions of IE, and remove it.

"const stylehacks = require('stylehacks');
const postcss = require('postcss');

postcss([ stylehacks() ])
.process('h1 { _color: red }', { from: undefined })
.then(result => {
  console.log(result.css);
  // Output will be 'h1 { }' as the hack is removed
});"

Whitelisting specific hacks

This feature allows users to lint for hacks without removing them, useful for cases where a hack is intentionally being used. The code sample shows how to use stylehacks in lint mode, which will not remove the hack but can be used to report or log its presence.

"const stylehacks = require('stylehacks');
const postcss = require('postcss');

postcss([ stylehacks({ lint: true }) ])
.process('h1 { _color: red }', { from: undefined })
.then(result => {
  console.log(result.css);
  // Output will be the same input 'h1 { _color: red }' as it only lints
});"

Other packages similar to stylehacks

postcss

While not exclusively focused on removing CSS hacks, PostCSS is a tool for transforming CSS with JavaScript plugins, one of which is stylehacks. PostCSS provides a broader range of functionalities for working with CSS, including autoprefixing, minification, and custom properties, making it more versatile but also more complex.

clean-css

clean-css is a fast and efficient CSS optimizer that can minify CSS files, including restructuring, removing unused CSS, and applying various optimizations. While it doesn't specifically target CSS hacks like stylehacks does, it contributes to the overall goal of optimizing and cleaning CSS files.

cssnano

cssnano is a modular CSS minifier that integrates with PostCSS, similar to stylehacks. It focuses on optimizing CSS files by reducing their size for production environments. cssnano includes functionalities for removing outdated browser prefixes, minifying font values, and discarding comments, among others. While it shares the goal of optimizing CSS, cssnano doesn't specifically target CSS hacks for removal but rather focuses on a wide range of optimizations.

README

stylehacks

Detect/remove browser hacks from CSS files.

Install

With npm do:

npm install stylehacks --save

Example

In its default mode, stylehacks will remove hacks from your CSS file, based on the browsers that you wish to support.

Input

h1 {
    _color: white;
    color: rgba(255, 255, 255, 0.5);
}

Output

h1 {
    color: rgba(255, 255, 255, 0.5);
}

API

stylehacks.detect(node)

Type: function
Returns: boolean

This method will take any PostCSS node, run applicable plugins depending on its type, then will return a boolean depending on whether it found any of the supported hacks. For example, if the decl node found below is passed to the detect function, it will return true. But if the rule node is passed, it will return false instead.

h1 { _color: red }

stylehacks.process(css, [options]).then(function(result) {})

options

browsers

Type: string|array
Default: browserslist defaults

Specify the browsers that you wish to support. The string will be passed directly to browserslist and parsed, however if an array is passed instead then stylehacks will use it instead of parsing the browsers itself.

lint

Type: boolean
Default: false

If lint mode is enabled, stylehacks will not remove hacks from the CSS; instead, it will warn that hacks were found. When using stylehacks as a PostCSS plugin, you are expected to handle these messages yourself.

silent

Type: boolean
Default: false

Used in combination with the lint option; disables all logging. When using the CLI, the process will exit with 0 or 1 as usual.

sourcemap

Type: boolean
Default: false

Generate a sourcemap with the transformed CSS.

postcss([ stylehacks(opts) ])

stylehacks can also be consumed as a PostCSS plugin. See the documentation for examples for your environment.

CLI

stylehacks also ships with a CLI app. To see the available options, just run:

$ stylehacks --help

Related

stylehacks works well with your existing PostCSS setup:

• stylelint - Comprehensive & modern CSS linter, to ensure that your code style rules are respected.

Contributing

Pull requests are welcome. If you add functionality, then please add unit tests to cover it.

License

MIT © Ben Briggs