deadweight

Deadweight is RCov for CSS, kind of. Given a set of stylesheets and a set of URLs, it determines which selectors are actually used and reports which can be “safely” deleted.

Simple example:

# lib/tasks/deadweight.rake

require 'deadweight'

description "run Deadweight (script/server needs to be running)"
task :deadweight do
  dw = Deadweight.new
  dw.stylesheets = %w( /stylesheets/style.css )
  dw.pages = %w( / /page/1 /about )
  puts dw.run
end

This will output all unused selectors, one per line.

Things to note:

By default, it looks at localhost:3000.
It’s completely dumb about any classes, IDs or tags that are only added by your Javascript layer, but you can filter them out by setting ignore_selectors.
You can optionally tell it to use Mechanize, and set up more complicated targets for scraping by specifying them as Procs.

More complex example:

# lib/tasks/deadweight.rake

require 'deadweight'

description "run Deadweight on staging server"
task :deadweight do
  dw = Deadweight.new

  dw.mechanize = true

  dw.root = 'http://staging.example.com'

  dw.stylesheets = %w( /stylesheets/style.css )

  dw.pages = %w( / /page/1 /about )

  dw.pages << proc {
    fetch('/login')
    form = agent.page.forms.first
    form.username = 'username'
    form.password = 'password'
    agent.submit(form)
    fetch('/secret-page')
  }

  dw.ignore_selectors = /hover|lightbox|superimposed_kittens/

  puts dw.run
end

deadweight

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