Sqwish-ruby

This as a Ruby bridge to Sqwish by Dustin Diaz to compress CSS very efficiently.

Just install it:

$ gem install sqwish

Then use it like so:

require 'sqwish'

Sqwish.minify "div { color: red; } div { background: black; }"
#=> "div{color:red}div{background:black}"

You can also use the strict: true flag (it defaults to false):

Sqwish.minify "div { color: red; } div { background: black; }", strict: true
#=> "div{color:red;background:black}"

In your Gemfile:

gem 'sqwish'

# or optionally:
gem 'sqwish', github: 'rstacruz/sqwish.rb'

In your config/environments/production.rb:

config.assets.css_compressor = Sqwish

# or use strict mode:
config.assets.css_compressor = Sqwish::Strict

If you use Sass (or a similar preprocessor), you probably separate your CSS definitions into multiple files. In Sass, there are two ways to do this:

/* Method 1: @import */
@import 'common';
@import 'layout';
@import 'chrome';
@import 'pages';

This is very convenient, and efficient in space, but slow. If you change one Sass file, the rest will have to be recompiled. In big projects, you can be waiting up to 10 seconds after updating a simple style.

Which leads us to method 2:

/* Method 2: Sprockets require */
//= require common
//= require layout
//= require chrome
//= require pages

This is faster! Updating one will no longer re-compile the others! The only problem here is that styles may be duplicated in each file, say, if each file depends on a web-font. You can end up with:

/* Method 1's crappy output with YUI :( */
@font-face{font-family:'Montserrat';...}
body{font-family:Montserrat}
@font-face{font-family:'Montserrat';...}
.page h1{font-family:Montserrat}

...which YUI (Rails/Sprocket's default compressor) will not optimize for you.

Use Sqwish! It will remove those duplicate @font-faces for you and combine anything else that can be combined.

/* Method 2's nice output with Sqwish :D */
@font-face{font-family:'Montserrat';...}
body,.page h1{font-family:Montserrat}

• Sqwish is by Dustin Diaz @ github.com/ded/sqwish.
• This Ruby gem is by Rico Sta. Cruz @ github.com/rstacruz/sqwish.rb.

Released under the MIT license.