postcss-url

PostCSS plugin to rebase, inline or copy on url().

Installation

$ npm install postcss-url

Basic example - rebase

// dependencies
const fs = require("fs")
const postcss = require("postcss")
const url = require("postcss-url")

// css to be processed
const css = fs.readFileSync("input.css", "utf8")

// process css
const output = postcss()
  .use(url({
    url: "rebase"
  }))
  .process(css, {
    from: "src/stylesheet/index.css",
    to: "dist/index.css"
  })

before:

.element {
    background: url('images/sprite.png');
}

after:

.element {
    /* rebasing path by new destination */
    background: url('../src/stylesheet/images/sprite.png');
}

Inline

// postcss-url options
const options = {
    url: 'inline'
};

postcss()
  .use(url(options))
  .process(css, {
    from: "src/stylesheet/index.css",
    to: "dist/index.css"
  })

before:

.element {
    background: url('/images/sprite.png');
    filter: url('/images/circle.svg');
}

after:

.element {
    /* inlined png as base64 */
    background: url('data:image/png;base64,R0lGODlhAQABAJH/AP///wAAAP///wAAACH/C0FET0JFOklSMS4');
    /* inlined svg as encodeURIComponent */
    filter: url('data:image/svg+xml,%3Csvg xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%2F%3E');
}

Copy

// postcss-url options
const options = {
    url: 'copy',
    // base path to search assets from
    basePath: path.resolve('node_modules/bootstrap'),
    // dir to copy assets
    assetsPath: 'img',
    // using hash names for assets (generates from asset content)
    useHash: true
};

postcss()
  .use(url(options))
  .process(css, {
    from: "src/stylesheet/index.css",
    to: "dist/index.css"
  })

before:

.element {
    background: url('/images/sprite.png');
}

after:

.element {
    /* copy 'sprite.png' from 'node_modules/bootstrap/images/' to 'dist/img/' */
    /* and rename it by hash function */
    background: url('img/a2ds3kfu.png');
}

Muiltiple options

const options = [
    { filter: '**/assets/copy/*.png', url: 'copy', assetsPath: 'img', useHash: true },
    { filter: '**/assets/inline/*.svg', url: 'inline' },
    { filter: '**/assets/**/*.gif', url: 'rebase' },
    // using custom function to build url
    { filter: 'cdn/**/*', url: (asset) => `https://cdn.url/${asset.url}` }
];

postcss().use(url(options))

Checkout tests for examples.

Options combinations

• rebase - default
• inline
  • basePath - path or array of paths to search assets (relative to from, or absolute)
  • encodeType - base64, encodeURI, encodeURIComponent
  • maxSize - file size in kbytes
  • fallback - copy or custom function for files > maxSize
• copy
  • basePath - path or array of paths to search assets (relative to from, or absolute)
  • assetsPath - directory to copy assets (relative to to or absolute)
  • useHash - use filehash(xxhash) for naming
  • hashOptions - options for hash function
• custom {Function}

Options list

url

rebase - (default)

Allow you to fix url() according to postcss to and/or from options (rebase to to first if available, otherwise from or process.cwd()).

inline

Allow you to inline assets using base64 encoding. Can use postcss from option to find ressources.

copy

Allow you to copy and rebase assets according to postcss to, assetsPath and from options (assetsPath is relative to the option to).

url: {Function}

Custom transform function. Takes following arguments:

• asset
  • url - original url
  • pathname - url pathname (url without search or hash)
  • absolutePath - absolute path to asset
  • relativePath - current relative path to asset
  • search - search from url, ex. ?query=1 from ./image.png?query=1
  • hash - hash from url, ex. #spriteLink from ../asset.svg#spriteLink
• dir
  • from - postcss option from
  • to - postcss option to
  • file - decl file path
• options - postcss-url matched options
• decl - related postcss declaration object
• warn - wrapped function result.warn for current decl
• result – postcss result object

And should return the transformed url. You can use this option to adjust urls for CDN.

maxSize

(default: 14)

Specify the maximum file size to inline (in kbytes)

filter

A regular expression e.g. /\.svg$/, a minimatch string e.g. '**/*.svg' or a custom filter function to determine wether a file should be inlined.

fallback

The url fallback method to use if max size is exceeded or url contains a hash. Custom transform functions are supported.

basePath

Specify the base path or list of base paths where to search images from

assetsPath

(default: false)

If you specify an assetsPath, the assets files will be copied in that destination

useHash

(default: false)

If set to true the copy method is going to rename the path of the files by a hash name

hashOptions

method

(default: xxhash32)

Hash method xxhash32|xxhash64 or custom function (accept file buffer)

shrink

(default: 8)

Result hash shrink count

Contributing

Work on a branch, install dev-dependencies, respect coding style & run tests before submitting a bug fix or a feature.

$ git clone https://github.com/postcss/postcss-url.git
$ git checkout -b patch-1
$ npm install
$ npm test

Changelog

License