grunt-autoprefixer

Autoprefixer parses CSS and adds vendor-prefixed CSS properties using the Can I Use database.

Getting Started

This plugin requires Grunt ~0.4.0

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-autoprefixer --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

grunt.loadNpmTasks('grunt-autoprefixer');

The "autoprefixer" task

Overview

In your project's Gruntfile, add a section named autoprefixer to the data object passed into grunt.initConfig().

grunt.initConfig({
  autoprefixer: {
    options: {
      // Task-specific options go here.
    },
    your_target: {
      // Target-specific file lists and/or options go here.
    },
  },
})

Options

options.browsers

Type: Array Default value: an array with default browsers

You can specify browsers actual for your project using this option:

options: {
  browsers: ['last 2 versions', 'ie 8', 'ie 9']
}

Or using a global config file named browserslist at the root of your project:

# Browsers that we support

> 5% in US
Last 2 versions

Read more about browserslist here.

options.cascade

Type: Boolean Default value: true

Pass false to disable ‘cascade’ indentation. Read more here.

options.remove

Type: Boolean Default value: true

Pass false to disable outdated prefixes cleaning. Read more here.

options.diff

Type: Boolean|String Default value: false

Set it to true if you want to get an output patch file:

options: {
  diff: true // or 'custom/path/to/file.css.patch'
}

Also you can specify a path where to save this file. More examples in Gruntfile.

options.map

Type: Boolean|Object Default value: false

If the map option isn't defined or is set to false, Autoprefixer will neither create nor update a sourcemap.

If true is specified, Autoprefixer will try to find a sourcemap from a previous compilation step using an annotation comment (e.g. from Sass) and create a new sourcemap based on the found one (or just create a new inlined sourcemap). The created sourcemap can be either a separate file or an inlined map depending on what the previous sourcemap was.

You can gain more control over sourcemap generation by setting an object to the map option:

• prev (string or false): a path to a directory where a previous sourcemap is (e.g. path/). By default, Autoprefixer will try to find a previous sourcemap using a path from the annotation comment (or using the annotation comment itself if the map is inlined). You can also set this option to false to delete the previous sourcemap.
• inline (boolean): whether a sourcemap will be inlined or not. By default, it will be the same as a previous sourcemap or inlined.
• annotation (string): set this option to URL path you wish the annotation comment to be e.g. path/file.css.map (by default, Autoprefixer will save your sourcemap to a directory where you save CSS). This option requires inline to be false or undefined.
• sourcesContent (boolean): whether original contents (e.g. Sass sources) will be included to a sourcemap. By default, Autoprefixer will add contents only for new sourcemaps or if a previous sourcemap has them.

options.safe

Type: Boolean Default value: false

Enable or disable PostCSS safe mode.

options: {
  safe: true
}

Usage Examples

grunt.initConfig({

  autoprefixer: {

    options: {
      // Task-specific options go here.
    },

    // prefix the specified file
    single_file: {
      options: {
        // Target-specific options go here.
      },
      src: 'src/css/file.css',
      dest: 'dest/css/file.css'
    },

    // prefix all files
    multiple_files: {
      files: [{
        expand: true,
        flatten: true,
        src: 'src/css/*.css', // -> src/css/file1.css, src/css/file2.css
        dest: 'dest/css/' // -> dest/css/file1.css, dest/css/file2.css
      }]
    },

    // if you have specified only the `src` param, the destination will be set automatically,
    // so source files will be overwritten
    no_dest: {
      src: 'dest/css/file.css' // globbing is also possible here
    },

    diff: {
        options: {
            diff: true
        },
        src: 'src/css/file.css',
        dest: 'dest/css/file.css' // -> dest/css/file.css, dest/css/file.css.patch
    },

    sourcemap: {
        options: {
            map: true
        },
        src: 'src/css/file.css',
        dest: 'dest/css/file.css' // -> dest/css/file.css, sourcemap is inlined
    },

    sourcemap_separate: {
        options: {
            map: {
                inline: false
            }
        },
        src: 'src/css/file.css',
        dest: 'dest/css/file.css' // -> dest/css/file.css, dest/css/file.css.map
    },
  }

});

Check out project's Gruntfile.js for more examples.

Updating prefixes database

$ npm update caniuse-db

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.