Only purge tailwind by default

Closes rails#5

Author: David Heinemeier Hansson

README.md

@@ -32,6 +32,11 @@ If you need to customize what files are searched for class names, you need to re
   config.assets.css_compressor = Tailwindcss::Compressor.new(files_with_class_names: Rails.root.glob("app/somehere/**/*.*"))
 ```
 
+By default, the CSS purger will only operate on the tailwind css file included with this gem. If you want to use it more broadly:
+
+```ruby
+  config.assets.css_compressor = Tailwindcss::Compressor.new(only_purge: %w[ tailwind and_my_other_css_file ])
+```
 
 ## License
 

lib/tailwindcss/compressor.rb

@@ -10,10 +10,17 @@ def self.call(input)
   end
 
   def initialize(options = {})
-    @options = { files_with_class_names: Rails.root.glob("app/views/**/*.*") + Rails.root.glob("app/helpers/**/*.rb") }.merge(options).freeze
+    @options = { 
+      files_with_class_names: Rails.root.glob("app/views/**/*.*") + Rails.root.glob("app/helpers/**/*.rb"),
+      only_purge: %w[ tailwind ]
+    }.merge(options).freeze
   end
 
   def call(input)
-    { data: Tailwindcss::Purger.purge(input[:data], keeping_class_names_from_files: @options[:files_with_class_names]) }
+    if input[:name].in?(@options[:only_purge])
+      { data: Tailwindcss::Purger.purge(input[:data], keeping_class_names_from_files: @options[:files_with_class_names]) }
+    else
+      input[:data]
+    end
   end
 end