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postcss-cli

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PostCSS CLI

Install

npm i -g|-D postcss-cli

Usage

postcss [input.css] [OPTIONS] [-o|--output output.css] [-w|--watch]

⚠️ If there are multiple input files, the --dir or --replace option must be passed.

cat input.css | postcss [OPTIONS] > output.css

⚠️ If no input files are passed, it reads from stdin. If neither -o, --dir, or --replace is passed, it writes to stdout.

Options

Name Type Default Description
-d, --dir {String} undefined Output Directory
-b, --base {String} undefined Use together with --dir for keeping directory structure.
-x, --ext {String} extname(output) Output File Extension
-o, --output {String} undefined Output File
-r, --replace {String} undefined Replace Input <=> Output
-p, --parser {String} undefined Custom PostCSS Parser
-s, --syntax {String} undefined Custom PostCSS Syntax
-t, --stringifier {String} undefined Custom PostCSS Stringifier
-w, --watch {Boolean} false Enable Watch Mode
--poll {Boolean} false Use polling for file watching
-u, --use {Array} [] PostCSS Plugins
-m, --map {Boolean} { inline: true } External Sourcemaps
--no-map {Boolean} false Disable Sourcemaps
-e, --env {String} process.env.NODE_ENV Sets $NODE_ENV
-c, --config {String} dirname(file) PostCSS Config Path postcss.config.js
-h, --help {Boolean} false CLI Help
-v, --version {Boolean} false CLI Version

ℹ️ More details on custom parsers, stringifiers and syntaxes, can be found here.

Config

If you need to pass options to your plugins, or have a long plugin chain, you'll want to use a configuration file.

postcss.config.js

module.exports = {
  parser: 'sugarss',
  plugins: [
    require('postcss-import')({...options}),
    require('postcss-url')({ url: 'copy', useHash: true })
  ]
}

Note that you can not set the from or to options for postcss in the config file. They are set automatically based on the CLI arguments.

Context

For more advanced usage it's recommend to to use a function in postcss.config.js, this gives you access to the CLI context to dynamically apply options and plugins per file

Name Type Default Description
env {String} 'development' process.env.NODE_ENV
file {Object} dirname, basename, extname File
options {Object} map, parser, syntax, stringifier PostCSS Options

postcss.config.js

module.exports = (ctx) => ({
  map: ctx.options.map,
  parser: ctx.file.extname === '.sss' ? 'sugarss' : false,
  plugins: {
    'postcss-import': { root: ctx.file.dirname }),
    'cssnano': ctx.env === 'production' ? {} : false
  }
})

⚠️ If you want to set options via CLI, it's mandatory to reference ctx.options in postcss.config.js

postcss input.sss -p sugarss -o output.css -m

postcss.config.js

module.exports = (ctx) => ({
  map: ctx.options.map,
  parser: ctx.options.parser,
  plugins: {
    'postcss-import': { root: ctx.file.dirname },
    'cssnano': ctx.env === 'production' ? {} : false
  }
})