ClassNames

ClassNames is a simple helper to conditionally join class names together.

Influenced by: https://www.npmjs.com/package/classnames and https://github.com/nLight/css-class-string

Installation

Add this line to your application's Gemfile:

gem 'class_names'

And then execute:

$ bundle

Or install it yourself as:

$ gem install class_names

Usage

Inside of a view:

  <span class="<%= class_names('foo', 'bar') %>">
  <!-- => <span class="foo bar"></span> -->
  
  <span class="<%= class_names('foo', { bar: true }) %>">
  <!-- => <span class="foo bar"></span> -->
  
  <span class="<%= class_names('foo-bar': true) %>">
  <!-- => <span class="foo-bar"></span> -->
  
  <span class="<%= class_names('foo-bar': false) %>">
  <!-- => <span class=""></span> -->
  
  <span class="<%= class_names(foo: true, bar: true) %>">
  <!-- => <span class="foo bar"></span> -->
  
  <span class="<%= class_names({ foo: true, bar: true }) %>">
  <!-- => <span class="foo bar"></span> -->
  
  <!-- Simple ternary replacement with multiple hashes -->
  <span class="<%= class_names([:truthy, :falsy] => true) %>">
  <!-- => <span class="truthy"></span> -->
  
  <span class="<%= class_names([:truthy, :falsy] => false) %>">
  <!-- => <span class="falsy"></span> -->
  
  <!-- Lots of different types of arguments -->
  <span class="<%= class_names(some: true, classy: true, [:truthy, :falsy] => false, 'foo') %>">
  <!-- equal to -->
  <span class="<%= class_names('some', 'classy', [:truthy, :falsy] => false %>, 'foo')">
  <!-- => <span class="some classy falsy foo"></span> -->

  %span{class: class_names(some: true, classy: false, [:truthy, :falsy] => true)}
  // equal to
  %span{class: class_names('some', falsy: false, [:truthy, :falsy] => true)}
  // => <span class="some truthy"></span>

Outside of a view:

ClassNames::Helper.new(:str_truthy => true, :str_falsy => false}).to_s
 => "str_truthy" 

ClassNames::Helper.new("truthy_1", "truthy_2").to_s
 => "truthy_1 truthy_2"

ClassNames::Helper.new({[:arr_truthy, :arr_falsy] => false}).to_s
 => "arr_falsy" 

Development

After checking out the repo, run bundle install to install dependencies. Then, run rake test to run the tests.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/abodo-dev/class_names. This project is intended to be a safe, welcoming space for collaboration.

Performance

On 50,000 calls. The unit of time is seconds.

	user	system	total	real
With 1 array and 1 string value	0.660000	0.000000	0.660000	(0.657901)
With 5 array and 5 string values	0.640000	0.000000	0.640000	(0.650673)
With 10 array values	0.450000	0.000000	0.450000	(0.449735)
With 10 string values	0.320000	0.010000	0.330000	(0.320911)