Autoprefixer Rails
Autoprefixer is a tool to parse CSS and add vendor prefixes to CSS rules using values from the Can I Use. This gem provides Ruby and Ruby on Rails integration with this JavaScript tool.
Usage
Windows users should install node.js. Autoprefixer Rails doesn’t work with old JScript in Windows.
Ruby on Rails
Add the autoprefixer-rails
gem to your Gemfile
:
gem "autoprefixer-rails"
Clear your cache:
rake tmp:clear
Write your CSS (Sass, Stylus, LESS) rules without vendor prefixes
and Autoprefixer will apply prefixes for you.
For example in app/assets/stylesheet/foobar.sass
:
:fullscreen a
display: flex
Autoprefixer uses Can I Use database with browser statistics and properties support to add vendor prefixes automatically using the Asset Pipeline:
:-webkit-full-screen a {
display: -webkit-box;
display: -webkit-flex;
display: flex
}
:-moz-full-screen a {
display: flex
}
:-ms-fullscreen a {
display: -ms-flexbox;
display: flex
}
:fullscreen a {
display: -webkit-box;
display: -webkit-flex;
display: -ms-flexbox;
display: flex
}
If you need to specify browsers for your Rails project, you can save them
to browserslist
config in app root. See Browserslist docs for config format.
last 1 version
> 1%
Explorer 10
You can get what properties will be changed using a Rake task:
rake autoprefixer:info
Sprockets
If you use Sinatra or other non-Rails frameworks with Sprockets, just connect your Sprockets environment with Autoprefixer and write CSS in the usual way:
assets = Sprockets::Environment.new do |env|
# Your assets settings
end
require "autoprefixer-rails"
AutoprefixerRails.install(assets)
Ruby
If you need to call Autoprefixer from plain Ruby code, it’s very easy:
require "autoprefixer-rails"
prefixed = AutoprefixerRails.process(css, from: 'main.css').css
You can specify browsers by browsers
option:
AutoprefixerRails.process(css, from: 'a.css', browsers: ['> 1%', 'ie 10']).css
Visual Cascade
By default, Autoprefixer will change CSS indentation to create nice visual cascade of prefixes.
a {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box
}
You can disable it by cascade: false
in config/autoprefixer.yml
or in process()
options.
Safe Mode
If you have legacy code with non-valid CSS hacks, you can enable Safe Mode and Autoprefixer will try to fix broken CSS.
Add safe: on
to config/autoprefixer.yml
or use safe: true
option
in process
method.
Source Map
Autoprefixer will generate source map, if you set map
option to true
in
process
method.
You must set input and output CSS files paths (by from
and to
options)
to generate correct map.
result = AutoprefixerRails.process(css,
map: true,
from: 'main.css',
to: 'main.out.css')
Autoprefixer can also modify previous source map (for example, from Sass
compilation). Just set original source map content (as string) to map
option:
result = AutoprefixerRails.process(css, {
map: File.read('main.sass.css.map'),
from: 'main.sass.css',
to: 'main.min.css')
result.map #=> Source map from main.sass to main.min.css
See all options in PostCSS docs. AutoprefixerRails will convert Ruby style
to JS style, so you can use map: { sources_content: false }
instead of camelcase sourcesContent
.