.config/coc/extensions/node_modules/coc-prettier/node_modules/postcss/README.md

   1 # PostCSS [![Gitter][chat-img]][chat]
   2
   3 <img align="right" width="95" height="95"
   4      alt="Philosopher’s stone, logo of PostCSS"
   5      src="http://postcss.github.io/postcss/logo.svg">
   6
   7 [chat-img]: https://img.shields.io/badge/Gitter-Join_the_PostCSS_chat-brightgreen.svg
   8 [chat]:     https://gitter.im/postcss/postcss
   9
  10 PostCSS is a tool for transforming styles with JS plugins.
  11 These plugins can lint your CSS, support variables and mixins,
  12 transpile future CSS syntax, inline images, and more.
  13
  14 PostCSS is used by industry leaders including Wikipedia, Twitter, Alibaba,
  15 and JetBrains. The [Autoprefixer] PostCSS plugin is one of the most popular
  16 CSS processors.
  17
  18 PostCSS takes a CSS file and provides an API to analyze and modify its rules
  19 (by transforming them into an [Abstract Syntax Tree]).
  20 This API can then be used by [plugins] to do a lot of useful things,
  21 e.g. to find errors automatically insert vendor prefixes.
  22
  23 **Support / Discussion:** [Gitter](https://gitter.im/postcss/postcss)<br>
  24 **Twitter account:**      [@postcss](https://twitter.com/postcss)<br>
  25 **VK.com page:**          [postcss](https://vk.com/postcss)<br>
  26 **中文翻译**:              [`README-cn.md`](./README-cn.md)
  27
  28 For PostCSS commercial support (consulting, improving the front-end culture
  29 of your company, PostCSS plugins), contact [Evil Martians](https://evilmartians.com/?utm_source=postcss)
  30 at <surrender@evilmartians.com>.
  31
  32 [Abstract Syntax Tree]: https://en.wikipedia.org/wiki/Abstract_syntax_tree
  33 [Autoprefixer]:         https://github.com/postcss/autoprefixer
  34 [plugins]:              https://github.com/postcss/postcss#plugins
  35
  36 <a href="https://evilmartians.com/?utm_source=postcss">
  37   <img src="https://evilmartians.com/badges/sponsored-by-evil-martians.svg"
  38        alt="Sponsored by Evil Martians" width="236" height="54">
  39 </a>
  40
  41 ## Plugins
  42
  43 Currently, PostCSS has more than 200 plugins. You can find all of the plugins
  44 in the [plugins list] or in the [searchable catalog]. Below is a list
  45 of our favorite plugins — the best demonstrations of what can be built
  46 on top of PostCSS.
  47
  48 If you have any new ideas, [PostCSS plugin development] is really easy.
  49
  50 [searchable catalog]: http://postcss.parts
  51 [plugins list]:       https://github.com/postcss/postcss/blob/master/docs/plugins.md
  52
  53 ### Solve Global CSS Problem
  54
  55 * [`postcss-use`] allows you to explicitly set PostCSS plugins within CSS
  56   and execute them only for the current file.
  57 * [`postcss-modules`] and [`react-css-modules`] automatically isolate
  58   selectors within components.
  59 * [`postcss-autoreset`] is an alternative to using a global reset
  60   that is better for isolatable components.
  61 * [`postcss-initial`] adds `all: initial` support, which resets
  62   all inherited styles.
  63 * [`cq-prolyfill`] adds container query support, allowing styles that respond
  64   to the width of the parent.
  65
  66 ### Use Future CSS, Today
  67
  68 * [`autoprefixer`] adds vendor prefixes, using data from Can I Use.
  69 * [`postcss-preset-env`] allows you to use future CSS features today.
  70
  71 ### Better CSS Readability
  72
  73 * [`precss`] contains plugins for Sass-like features, like variables, nesting,
  74   and mixins.
  75 * [`postcss-sorting`] sorts the content of rules and at-rules.
  76 * [`postcss-utilities`] includes the most commonly used shortcuts and helpers.
  77 * [`short`] adds and extends numerous shorthand properties.
  78
  79 ### Images and Fonts
  80
  81 * [`postcss-assets`] inserts image dimensions and inlines files.
  82 * [`postcss-sprites`] generates image sprites.
  83 * [`font-magician`] generates all the `@font-face` rules needed in CSS.
  84 * [`postcss-inline-svg`] allows you to inline SVG and customize its styles.
  85 * [`postcss-write-svg`] allows you to write simple SVG directly in your CSS.
  86
  87 ### Linters
  88
  89 * [`stylelint`] is a modular stylesheet linter.
  90 * [`stylefmt`] is a tool that automatically formats CSS
  91   according `stylelint` rules.
  92 * [`doiuse`] lints CSS for browser support, using data from Can I Use.
  93 * [`colorguard`] helps you maintain a consistent color palette.
  94
  95 ### Other
  96
  97 * [`postcss-rtl`] combines both-directional (left-to-right and right-to-left) styles in one CSS file.
  98 * [`cssnano`] is a modular CSS minifier.
  99 * [`lost`] is a feature-rich `calc()` grid system.
 100 * [`rtlcss`] mirrors styles for right-to-left locales.
 101
 102 [PostCSS plugin development]:   https://github.com/postcss/postcss/blob/master/docs/writing-a-plugin.md
 103 [`postcss-inline-svg`]:         https://github.com/TrySound/postcss-inline-svg
 104 [`postcss-preset-env`]:         https://github.com/jonathantneal/postcss-preset-env
 105 [`react-css-modules`]:          https://github.com/gajus/react-css-modules
 106 [`postcss-autoreset`]:          https://github.com/maximkoretskiy/postcss-autoreset
 107 [`postcss-write-svg`]:          https://github.com/jonathantneal/postcss-write-svg
 108 [`postcss-utilities`]:          https://github.com/ismamz/postcss-utilities
 109 [`postcss-initial`]:            https://github.com/maximkoretskiy/postcss-initial
 110 [`postcss-sprites`]:            https://github.com/2createStudio/postcss-sprites
 111 [`postcss-modules`]:            https://github.com/outpunk/postcss-modules
 112 [`postcss-sorting`]:            https://github.com/hudochenkov/postcss-sorting
 113 [`postcss-assets`]:             https://github.com/assetsjs/postcss-assets
 114 [`font-magician`]:              https://github.com/jonathantneal/postcss-font-magician
 115 [`autoprefixer`]:               https://github.com/postcss/autoprefixer
 116 [`cq-prolyfill`]:               https://github.com/ausi/cq-prolyfill
 117 [`postcss-rtl`]:                https://github.com/vkalinichev/postcss-rtl
 118 [`postcss-use`]:                https://github.com/postcss/postcss-use
 119 [`css-modules`]:                https://github.com/css-modules/css-modules
 120 [`colorguard`]:                 https://github.com/SlexAxton/css-colorguard
 121 [`stylelint`]:                  https://github.com/stylelint/stylelint
 122 [`stylefmt`]:                   https://github.com/morishitter/stylefmt
 123 [`cssnano`]:                    http://cssnano.co
 124 [`precss`]:                     https://github.com/jonathantneal/precss
 125 [`doiuse`]:                     https://github.com/anandthakker/doiuse
 126 [`rtlcss`]:                     https://github.com/MohammadYounes/rtlcss
 127 [`short`]:                      https://github.com/jonathantneal/postcss-short
 128 [`lost`]:                       https://github.com/peterramsing/lost
 129
 130 ## Syntaxes
 131
 132 PostCSS can transform styles in any syntax, not just CSS.
 133 If there is not yet support for your favorite syntax,
 134 you can write a parser and/or stringifier to extend PostCSS.
 135
 136 * [`sugarss`] is a indent-based syntax like Sass or Stylus.
 137 * [`postcss-syntax`] switch syntax automatically by file extensions.
 138 * [`postcss-html`] parsing styles in `<style>` tags of HTML-like files.
 139 * [`postcss-markdown`] parsing styles in code blocks of Markdown files.
 140 * [`postcss-jsx`] parsing CSS in template / object literals of source files.
 141 * [`postcss-styled`] parsing CSS in template literals of source files.
 142 * [`postcss-scss`] allows you to work with SCSS
 143   *(but does not compile SCSS to CSS)*.
 144 * [`postcss-sass`] allows you to work with Sass
 145     *(but does not compile Sass to CSS)*.
 146 * [`postcss-less`] allows you to work with Less
 147   *(but does not compile LESS to CSS)*.
 148 * [`postcss-less-engine`] allows you to work with Less
 149   *(and DOES compile LESS to CSS using true Less.js evaluation)*.
 150 * [`postcss-js`] allows you to write styles in JS or transform
 151   React Inline Styles, Radium or JSS.
 152 * [`postcss-safe-parser`] finds and fixes CSS syntax errors.
 153 * [`midas`] converts a CSS string to highlighted HTML.
 154
 155 [`postcss-less-engine`]: https://github.com/Crunch/postcss-less
 156 [`postcss-safe-parser`]: https://github.com/postcss/postcss-safe-parser
 157 [`postcss-syntax`]:      https://github.com/gucong3000/postcss-syntax
 158 [`postcss-html`]:        https://github.com/gucong3000/postcss-html
 159 [`postcss-markdown`]:    https://github.com/gucong3000/postcss-markdown
 160 [`postcss-jsx`]:         https://github.com/gucong3000/postcss-jsx
 161 [`postcss-styled`]:      https://github.com/gucong3000/postcss-styled
 162 [`postcss-scss`]:        https://github.com/postcss/postcss-scss
 163 [`postcss-sass`]:        https://github.com/AleshaOleg/postcss-sass
 164 [`postcss-less`]:        https://github.com/webschik/postcss-less
 165 [`postcss-js`]:          https://github.com/postcss/postcss-js
 166 [`sugarss`]:             https://github.com/postcss/sugarss
 167 [`midas`]:               https://github.com/ben-eb/midas
 168
 169 ## Articles
 170
 171 * [Some things you may think about PostCSS… and you might be wrong](http://julian.io/some-things-you-may-think-about-postcss-and-you-might-be-wrong)
 172 * [What PostCSS Really Is; What It Really Does](http://davidtheclark.com/its-time-for-everyone-to-learn-about-postcss)
 173 * [PostCSS Guides](http://webdesign.tutsplus.com/series/postcss-deep-dive--cms-889)
 174
 175 More articles and videos you can find on [awesome-postcss](https://github.com/jjaderg/awesome-postcss) list.
 176
 177 ## Books
 178
 179 * [Mastering PostCSS for Web Design](https://www.packtpub.com/web-development/mastering-postcss-web-design) by Alex Libby, Packt. (June 2016)
 180
 181 ## Usage
 182
 183 You can start using PostCSS in just two steps:
 184
 185 1. Find and add PostCSS extensions for your build tool.
 186 2. [Select plugins] and add them to your PostCSS process.
 187
 188 [Select plugins]: http://postcss.parts
 189
 190 ### Webpack
 191
 192 Use [`postcss-loader`] in `webpack.config.js`:
 193
 194 ```js
 195 module.exports = {
 196     module: {
 197         rules: [
 198             {
 199                 test: /\.css$/,
 200                 exclude: /node_modules/,
 201                 use: [
 202                     {
 203                         loader: 'style-loader',
 204                     },
 205                     {
 206                         loader: 'css-loader',
 207                         options: {
 208                             importLoaders: 1,
 209                         }
 210                     },
 211                     {
 212                         loader: 'postcss-loader'
 213                     }
 214                 ]
 215             }
 216         ]
 217     }
 218 }
 219 ```
 220
 221 Then create `postcss.config.js`:
 222
 223 ```js
 224 module.exports = {
 225     plugins: [
 226         require('precss'),
 227         require('autoprefixer')
 228     ]
 229 }
 230 ```
 231
 232 [`postcss-loader`]: https://github.com/postcss/postcss-loader
 233
 234 ### Gulp
 235
 236 Use [`gulp-postcss`] and [`gulp-sourcemaps`].
 237
 238 ```js
 239 gulp.task('css', function () {
 240     var postcss    = require('gulp-postcss');
 241     var sourcemaps = require('gulp-sourcemaps');
 242
 243     return gulp.src('src/**/*.css')
 244         .pipe( sourcemaps.init() )
 245         .pipe( postcss([ require('precss'), require('autoprefixer') ]) )
 246         .pipe( sourcemaps.write('.') )
 247         .pipe( gulp.dest('build/') );
 248 });
 249 ```
 250
 251 [`gulp-sourcemaps`]: https://github.com/floridoo/gulp-sourcemaps
 252 [`gulp-postcss`]:    https://github.com/postcss/gulp-postcss
 253
 254 ### npm run / CLI
 255
 256 To use PostCSS from your command-line interface or with npm scripts
 257 there is [`postcss-cli`].
 258
 259 ```sh
 260 postcss --use autoprefixer -c options.json -o main.css css/*.css
 261 ```
 262
 263 [`postcss-cli`]: https://github.com/postcss/postcss-cli
 264
 265 ### Browser
 266
 267 If you want to compile CSS string in browser (for instance, in live edit
 268 tools like CodePen), just use [Browserify] or [webpack]. They will pack
 269 PostCSS and plugins files into a single file.
 270
 271 To apply PostCSS plugins to React Inline Styles, JSS, Radium
 272 and other [CSS-in-JS], you can use [`postcss-js`] and transforms style objects.
 273
 274 ```js
 275 var postcss  = require('postcss-js');
 276 var prefixer = postcss.sync([ require('autoprefixer') ]);
 277
 278 prefixer({ display: 'flex' }); //=> { display: ['-webkit-box', '-webkit-flex', '-ms-flexbox', 'flex'] }
 279 ```
 280
 281 [`postcss-js`]: https://github.com/postcss/postcss-js
 282 [Browserify]:   http://browserify.org/
 283 [CSS-in-JS]:    https://github.com/MicheleBertoli/css-in-js
 284 [webpack]:      https://webpack.github.io/
 285
 286 ### Runners
 287
 288 * **Grunt**: [`grunt-postcss`](https://github.com/nDmitry/grunt-postcss)
 289 * **HTML**: [`posthtml-postcss`](https://github.com/posthtml/posthtml-postcss)
 290 * **Stylus**: [`poststylus`](https://github.com/seaneking/poststylus)
 291 * **Rollup**: [`rollup-plugin-postcss`](https://github.com/egoist/rollup-plugin-postcss)
 292 * **Brunch**: [`postcss-brunch`](https://github.com/brunch/postcss-brunch)
 293 * **Broccoli**: [`broccoli-postcss`](https://github.com/jeffjewiss/broccoli-postcss)
 294 * **Meteor**: [`postcss`](https://atmospherejs.com/juliancwirko/postcss)
 295 * **ENB**: [`enb-postcss`](https://github.com/awinogradov/enb-postcss)
 296 * **Taskr**: [`taskr-postcss`](https://github.com/lukeed/taskr/tree/master/packages/postcss)
 297 * **Start**: [`start-postcss`](https://github.com/start-runner/postcss)
 298 * **Connect/Express**: [`postcss-middleware`](https://github.com/jedmao/postcss-middleware)
 299
 300 ### JS API
 301
 302 For other environments, you can use the JS API:
 303
 304 ```js
 305 const fs = require('fs');
 306 const postcss = require('postcss');
 307 const precss = require('precss');
 308 const autoprefixer = require('autoprefixer');
 309
 310 fs.readFile('src/app.css', (err, css) => {
 311     postcss([precss, autoprefixer])
 312         .process(css, { from: 'src/app.css', to: 'dest/app.css' })
 313         .then(result => {
 314             fs.writeFile('dest/app.css', result.css, () => true);
 315             if ( result.map ) {
 316                 fs.writeFile('dest/app.css.map', result.map, () => true);
 317             }
 318         });
 319 });
 320 ```
 321
 322 Read the [PostCSS API documentation] for more details about the JS API.
 323
 324 All PostCSS runners should pass [PostCSS Runner Guidelines].
 325
 326 [PostCSS Runner Guidelines]: https://github.com/postcss/postcss/blob/master/docs/guidelines/runner.md
 327 [PostCSS API documentation]: http://api.postcss.org/postcss.html
 328
 329 ### Options
 330
 331 Most PostCSS runners accept two parameters:
 332
 333 * An array of plugins.
 334 * An object of options.
 335
 336 Common options:
 337
 338 * `syntax`: an object providing a syntax parser and a stringifier.
 339 * `parser`: a special syntax parser (for example, [SCSS]).
 340 * `stringifier`: a special syntax output generator (for example, [Midas]).
 341 * `map`: [source map options].
 342 * `from`: the input file name (most runners set it automatically).
 343 * `to`: the output file name (most runners set it automatically).
 344
 345 [source map options]: https://github.com/postcss/postcss/blob/master/docs/source-maps.md
 346 [Midas]:              https://github.com/ben-eb/midas
 347 [SCSS]:               https://github.com/postcss/postcss-scss
 348
 349 ## Editors & IDE Integration
 350
 351 ### Atom
 352
 353 * [`language-postcss`] adds PostCSS and [SugarSS] highlight.
 354 * [`source-preview-postcss`] previews your output CSS in a separate, live pane.
 355
 356 [SugarSS]: https://github.com/postcss/sugarss
 357
 358 ### Sublime Text
 359
 360 * [`Syntax-highlighting-for-PostCSS`] adds PostCSS highlight.
 361
 362 [`Syntax-highlighting-for-PostCSS`]: https://github.com/hudochenkov/Syntax-highlighting-for-PostCSS
 363 [`source-preview-postcss`]:          https://atom.io/packages/source-preview-postcss
 364 [`language-postcss`]:                https://atom.io/packages/language-postcss
 365
 366 ### Vim
 367
 368 * [`postcss.vim`] adds PostCSS highlight.
 369
 370 [`postcss.vim`]: https://github.com/stephenway/postcss.vim
 371
 372 ### WebStorm
 373
 374 WebStorm 2016.3 [has] built-in PostCSS support.
 375
 376 [has]: https://blog.jetbrains.com/webstorm/2016/08/webstorm-2016-3-early-access-preview/