Add support for sorting TailwindCSS class names

.gitignore

@@ -7,3 +7,4 @@
 /spec/reports/
 /tmp/
 /Gemfile.lock
+/test/fixtures/tailwindcss/class_sorting.css

README.md

@@ -125,6 +125,12 @@ After checking out the repo, run `bin/setup` to install dependencies. Then, run
 
 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 the created tag, and push the `.gem` file to [rubygems.org](https://rubygems.org).
 
+In order to run a specific test, use the following command:
+
+```bash
+m test/erb/test_formatter.rb:123
+```
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/nebulab/erb-formatter.

erb-formatter.gemspec

@@ -29,4 +29,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_dependency "syntax_tree", '~> 6.0'
+
+  spec.add_development_dependency "tailwindcss-rails", "~> 2.0"
+  spec.add_development_dependency "m", "~> 1.0"
 end

lib/erb/formatter.rb

@@ -75,14 +75,15 @@ def self.format(source, filename: nil)
     new(source, filename: filename).html
   end
 
-  def initialize(source, line_width: 80, single_class_per_line: false, filename: nil, debug: $DEBUG)
+  def initialize(source, line_width: 80, single_class_per_line: false, filename: nil, css_class_sorter: nil, debug: $DEBUG)
     @original_source = source
     @filename = filename || '(erb)'
     @line_width = line_width
     @source = remove_front_matter source.dup
     @html = +""
     @debug = debug
     @single_class_per_line = single_class_per_line
+    @css_class_sorter = css_class_sorter
 
     html.extend DebugShovel if @debug
 
@@ -125,7 +126,9 @@ def format_attributes(tag_name, attrs, tag_closing)
     return "" if attrs.strip.empty?
 
     plain_attrs = attrs.tr("\n", " ").squeeze(" ").gsub(erb_tags_regexp, erb_tags)
-    return " #{plain_attrs}" if "<#{tag_name} #{plain_attrs}#{tag_closing}".size <= line_width
+    within_line_width = "<#{tag_name} #{plain_attrs}#{tag_closing}".size <= line_width
+
+    return " #{plain_attrs}" if within_line_width && !@css_class_sorter && !plain_attrs.match?(/ class=/)
 
     attr_html = ""
     tag_stack_push(['attr='], attrs)
@@ -140,8 +143,10 @@ def format_attributes(tag_name, attrs, tag_closing)
       end
 
       value_parts = value[1...-1].strip.split(/\s+/)
+      value_parts.sort_by!(&@css_class_sorter) if name == 'class' && @css_class_sorter
 
-      full_attr = indented("#{name}=#{value[0]}#{value_parts.join(" ")}#{value[-1]}")
+      full_attr = "#{name}=#{value[0]}#{value_parts.join(" ")}#{value[-1]}"
+      full_attr = within_line_width ? " #{full_attr}" : indented(full_attr)
 
       if full_attr.size > line_width && MULTILINE_ATTR_NAMES.include?(name) && attr.match?(QUOTED_ATTR)
         attr_html << indented("#{name}=#{value[0]}")
@@ -165,14 +170,14 @@ def format_attributes(tag_name, attrs, tag_closing)
         end
 
         tag_stack_pop('attr"', value)
-        attr_html << indented(value[-1])
+        attr_html << (within_line_width ? value[-1] : indented(value[-1]))
       else
         attr_html << full_attr
       end
     end
 
     tag_stack_pop(['attr='], attrs)
-    attr_html << indented("")
+    attr_html << indented("") unless within_line_width
     attr_html
   end
 

lib/erb/formatter/command_line.rb

@@ -3,6 +3,19 @@
 require 'optparse'
 
 class ERB::Formatter::CommandLine
+  def self.tailwindcss_class_sorter(css_path)
+    css = File.read(css_path)
+
+    css = css.tr("\n", " ").gsub(%r{\/\*.*?\*\/},"") # remove comments
+    css = css.gsub(%r<@media.*?\{>, "") # strip media queries
+    css = css.scan(%r<(?:^|\}|\{) *(\S.*?) *\{>).join(" ") # extract selectors
+    classes = css.tr(","," ").split(" ").grep(/\./).uniq.map { _1.split('.').last.gsub("\\", "") }
+    indexed_classes = Hash[classes.zip((0...classes.size).to_a)]
+
+    ->(class_name) do
+      indexed_classes[class_name] || classes.index { _1.start_with?(class_name) } || -1
+    end
+  end
 
   attr_reader :write, :filename, :read_stdin
 
@@ -41,6 +54,10 @@ def initialize(argv, stdin: $stdin)
         @single_class_per_line = value
       end
 
+      parser.on("--tailwind-output-path PATH", "Set the path to the tailwind output file") do |value|
+        @tailwind_output_path = value
+      end
+
       parser.on("--[no-]debug", "Enable debug mode") do |value|
         $DEBUG = value
       end
@@ -61,10 +78,6 @@ def ignore_list
     @ignore_list ||= ERB::Formatter::IgnoreList.new
   end
 
-  def ignore?(filename)
-
-  end
-
   def run
     if read_stdin
       abort "Can't read both stdin and a list of files" unless @argv.empty?
@@ -77,11 +90,21 @@ def run
       end
     end
 
+    if @tailwind_output_path
+      css_class_sorter = self.class.tailwindcss_class_sorter(@tailwind_output_path)
+    end
+
     files.each do |(filename, code)|
       if ignore_list.should_ignore_file? filename
         print code unless write
       else
-        html = ERB::Formatter.new(code, filename: filename, line_width: @width || 80, single_class_per_line: @single_class_per_line)
+        html = ERB::Formatter.new(
+          code,
+          filename: filename,
+          line_width: @width || 80,
+          single_class_per_line: @single_class_per_line,
+          css_class_sorter: css_class_sorter
+        )
 
         if write
           File.write(filename, html)

test/erb/test_formatter.rb

@@ -16,7 +16,7 @@ def test_fixtures
       expected_path = erb_path.chomp('.erb') + '.expected.erb'
 
       # File.write expected_path, ERB::Formatter.format(File.read(erb_path))
-      assert_equal(File.read(expected_path), ERB::Formatter.format(File.read(erb_path)), "Formatting of #{erb_path} failed")
+      assert_equal(File.read(expected_path), ERB::Formatter.new(File.read(erb_path)).to_s, "Formatting of #{erb_path} failed")
     end
   end
 
@@ -156,4 +156,29 @@ def test_format_ruby_with_long_lines_and_larger_line_width
       ).to_s,
     )
   end
+
+  def test_tailwindcss_class_sorting
+    require 'tailwindcss-rails'
+    require 'erb/formatter/command_line'
+
+    error_log = "#{__dir__}/../../tmp/tailwindcss.err.log"
+    Dir.mkdir(File.dirname(error_log)) unless File.exist?(File.dirname(error_log))
+
+    system(
+      Tailwindcss::Commands.executable,
+      "--content", "#{__dir__}/../fixtures/tailwindcss/class_sorting.html.erb",
+      "--output", "#{__dir__}/../fixtures/tailwindcss/class_sorting.css",
+      err: error_log,
+    ) || raise("Failed to generate tailwindcss output:\n#{File.read(error_log)}")
+
+    css_class_sorter = ERB::Formatter::CommandLine.tailwindcss_class_sorter("#{__dir__}/../fixtures/tailwindcss/class_sorting.css")
+
+    assert_equal(
+      File.read("#{__dir__}/../fixtures/tailwindcss/class_sorting.html.expected.erb"),
+      ERB::Formatter.new(
+        File.read("#{__dir__}/../fixtures/tailwindcss/class_sorting.html.erb"),
+        css_class_sorter: css_class_sorter,
+      ).to_s,
+    )
+  end
 end

test/fixtures/tailwindcss/class_sorting.html.erb

@@ -0,0 +1,14 @@
+<div class="pt-2 p-4">
+</div>
+
+<div class="text-gray-700 shadow-md p-3 border-gray-300 ml-4 h-24 flex border-2">
+</div>
+
+<div class="hover:opacity-75 opacity-50 hover:scale-150 scale-125">
+</div>
+
+<div class="lg:grid-cols-4 grid sm:grid-cols-3 grid-cols-2">
+</div>
+
+<div class="p-3 shadow-xl select2-dropdown">
+</div>

test/fixtures/tailwindcss/class_sorting.html.expected.erb

@@ -0,0 +1,16 @@
+<div class="p-4 pt-2">
+</div>
+
+<div
+  class="ml-4 flex h-24 border-2 border-gray-300 p-3 text-gray-700 shadow-md"
+>
+</div>
+
+<div class="scale-125 opacity-50 hover:scale-150 hover:opacity-75">
+</div>
+
+<div class="grid grid-cols-2 sm:grid-cols-3 lg:grid-cols-4">
+</div>
+
+<div class="select2-dropdown p-3 shadow-xl">
+</div>