Use Sprockets compressor for purging

David Heinemeier Hansson · David Heinemeier Hansson · commit c941c5aa8850 · 2021-01-13T14:21:31.000+01:00
diff --git a/lib/install/tailwindcss.rb b/lib/install/tailwindcss.rb
@@ -7,3 +7,6 @@
   say "Default application.html.erb is missing!", :red
   say %(        Add <%= stylesheet_link_tag "tailwind" %> within the <head> tag in your custom layout.)
 end
+
+say "Turn on purging of unused css classes in production"
+append_to_file Rails.root.join("app/config/environments/production.rb"), %(  config.assets.css_compressor = :purger)
diff --git a/lib/tailwindcss-rails.rb b/lib/tailwindcss-rails.rb
@@ -3,3 +3,4 @@ module Tailwindcss
 
 require "tailwindcss/version"
 require "tailwindcss/engine"
+require "tailwindcss/compressor"
diff --git a/lib/tailwindcss/compressor.rb b/lib/tailwindcss/compressor.rb
@@ -0,0 +1,20 @@
+require "tailwindcss/purger"
+
+class Tailwindcss::Compressor
+  def self.instance
+    @instance ||= new
+  end
+
+  def self.call(input)
+    instance.call(input)
+  end
+
+  def initialize(options = {})
+    @options = { paths_with_css_class_names: [ "app/views/**/*.*", "app/helpers/**/*.rb" ] }.merge(options).freeze
+    @purger  = Tailwindcss::Purger.new(@options)
+  end
+
+  def call(input)
+    { data: @purger.purge(input[:data]) }
+  end
+end
diff --git a/lib/tailwindcss/engine.rb b/lib/tailwindcss/engine.rb
@@ -2,6 +2,10 @@
 
 module Tailwindcss
   class Engine < ::Rails::Engine
+    initializer "tailwindcss.compressor" do
+      Sprockets.register_compressor "text/css", :purger, Tailwindcss::Compressor
+    end
+
     initializer "tailwindcss.assets" do
       Rails.application.config.assets.precompile += %w( tailwind )
     end
diff --git a/lib/tailwindcss/purger.rb b/lib/tailwindcss/purger.rb
@@ -1,15 +1,15 @@
 class Tailwindcss::Purger
-  attr_reader :stylesheet_path, :paths_with_css_class_names
+  attr_reader :paths_with_css_class_names
 
-  def initialize(stylesheet_path:, paths_with_css_class_names:)
-    @stylesheet_path, @paths_with_css_class_names = stylesheet_path, paths_with_css_class_names
+  def initialize(paths_with_css_class_names:)
+    @paths_with_css_class_names = paths_with_css_class_names
   end
 
-  def purge
+  def purge(input)
     inside_valid_selector = inside_invalid_selector = false
     output = []
 
-    stylesheet_path.readlines.each do |line|
+    input.split("\n").each do |line|
       case
       when inside_valid_selector
         output << line
diff --git a/lib/tasks/tailwindcss_tasks.rake b/lib/tasks/tailwindcss_tasks.rake
@@ -3,11 +3,4 @@ namespace :tailwindcss do
   task :install do
     system "#{RbConfig.ruby} ./bin/rails app:template LOCATION=#{File.expand_path("../install/tailwindcss.rb", __dir__)}"
   end
-
-  task :purge do
-    Tailwindcss::Purger.new(
-      stylesheet_path: Rails.root.join("public/assets").glob("tailwindcss-*.css").first,
-      paths_with_css_class_names: [ "app/views/**/*.html*", "app/helpers/**/*.rb" ]
-    ).purge
-  end
 end

Original file line number	Diff line number	Diff line change
`@@ -3,3 +3,4 @@ module Tailwindcss`
`3`	`3`
`4`	`4`	`require "tailwindcss/version"`
`5`	`5`	`require "tailwindcss/engine"`
	`6`	`+require "tailwindcss/compressor"`