Break class attributes at line width instead of using one class per line

lib/erb/formatter.rb

@@ -56,13 +56,6 @@ class Error < StandardError; end
 
   RUBOCOP_STDIN_MARKER = "===================="
 
-  # Override the max line length to account from already indented ERB
-  module RubocopForcedMaxLineLength
-    def max
-      Thread.current['RuboCop::Cop::Layout::LineLength#max'] || super
-    end
-  end
-
   module DebugShovel
     def <<(string)
       puts "ADDING: #{string.inspect} FROM:\n  #{caller(1, 5).join("\n  ")}"
@@ -74,13 +67,14 @@ def self.format(source, filename: nil)
     new(source, filename: filename).html
   end
 
-  def initialize(source, line_width: 80, filename: nil, debug: $DEBUG)
+  def initialize(source, line_width: 80, single_class_per_line: false, filename: 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
 
     html.extend DebugShovel if @debug
 
@@ -127,6 +121,7 @@ def format_attributes(tag_name, attrs, tag_closing)
 
     attr_html = ""
     tag_stack_push(['attr='], attrs)
+
     attrs.scan(ATTR).flatten.each do |attr|
       attr.strip!
       full_attr = indented(attr)
@@ -135,15 +130,33 @@ def format_attributes(tag_name, attrs, tag_closing)
       if full_attr.size > line_width && MULTILINE_ATTR_NAMES.include?(name) && attr.match?(QUOTED_ATTR)
         attr_html << indented("#{name}=#{value[0]}")
         tag_stack_push('attr"', value)
-        value[1...-1].strip.split(/\s+/).each do |value_part|
-          attr_html << indented(value_part)
+
+        value_parts = value[1...-1].strip.split(/\s+/)
+
+        if !@single_class_per_line && name == 'class'
+          line = value_parts.shift
+          value_parts.each do |value_part|
+            if (line.size + value_part.size + 1) <= line_width
+              line << " #{value_part}"
+            else
+              attr_html << indented(line)
+              line = value_part
+            end
+          end
+          attr_html << indented(line) if line
+        else
+          value_parts.each do |value_part|
+            attr_html << indented(value_part)
+          end
         end
+
         tag_stack_pop('attr"', value)
         attr_html << indented(value[-1])
       else
         attr_html << full_attr
       end
     end
+
     tag_stack_pop(['attr='], attrs)
     attr_html << indented("")
     attr_html

lib/erb/formatter/command_line.rb

@@ -10,7 +10,7 @@ def initialize(argv, stdin: $stdin)
     @argv = argv.dup
     @stdin = stdin
 
-    @write, @filename, @read_stdin, @code = nil
+    @write, @filename, @read_stdin, @code, @single_class_per_line = nil
 
     OptionParser.new do |parser|
       parser.banner = "Usage: #{$0} FILENAME... --write"
@@ -37,6 +37,10 @@ def initialize(argv, stdin: $stdin)
         @width = value
       end
 
+      parser.on("--single-class-per-line", "Print each class on a separate line") do |value|
+        @single_class_per_line = value
+      end
+
       parser.on("--[no-]debug", "Enable debug mode") do |value|
         $DEBUG = value
       end
@@ -77,7 +81,7 @@ def run
       if ignore_list.should_ignore_file? filename
         print code unless write
       else
-        html = ERB::Formatter.new(code, filename: filename, line_width: @width || 80)
+        html = ERB::Formatter.new(code, filename: filename, line_width: @width || 80, single_class_per_line: @single_class_per_line)
 
         if write
           File.write(filename, html)

test/fixtures/multiline_attributes.html.erb

@@ -0,0 +1,3 @@
+<button class="text-gray-700 bg-transparent hover:bg-gray-50 active:bg-gray-100 focus:bg-gray-50 focus:ring-gray-300 focus:ring-2
+disabled:text-gray-300 disabled:bg-transparent disabled:border-gray-300 disabled:cursor-not-allowed
+aria-disabled:text-gray-300 aria-disabled:bg-transparent aria-disabled:border-gray-300 aria-disabled:cursor-not-allowed">Button</button>

test/fixtures/multiline_attributes.html.expected.erb

@@ -0,0 +1,9 @@
+<button
+  class="
+    text-gray-700 bg-transparent hover:bg-gray-50 active:bg-gray-100
+    focus:bg-gray-50 focus:ring-gray-300 focus:ring-2 disabled:text-gray-300
+    disabled:bg-transparent disabled:border-gray-300 disabled:cursor-not-allowed
+    aria-disabled:text-gray-300 aria-disabled:bg-transparent
+    aria-disabled:border-gray-300 aria-disabled:cursor-not-allowed
+  "
+>Button</button>