Genreate report on possible duplicate and missing scss color vars

scss_color_extractor.rb

require 'scss_lint'

module SassExtractor
  mattr_accessor :color_var_nodes
  mattr_accessor :color_nodes
  self.color_var_nodes = []
  self.color_nodes     = []

  module Vistors
    class VariableGatherer < SCSSLint::Linter

      def visit_variable(node)
        if node.expr.is_a?(Sass::Script::Tree::Literal) && node.expr.value.is_a?(Sass::Script::Value::Color)
          SassExtractor.color_var_nodes << node
        end
      end

    end
    class ColorGatherer < SCSSLint::Linter

      def visit_script_color(node)
        unless node.to_s == 'transparent' || debug_line(node) =~ /\$(.*?):(.*?);/
          SassExtractor.color_nodes << [node, node.to_s, debug_line(node)]
        end
      end

      def visit_script_string(node)
        return unless node.type == :identifier
        value = remove_quoted_strings(node.value)
        # Hexs
        value.scan(/#(?:[0-9a-f]{3}){1,2}/i) do |color|
          SassExtractor.color_nodes << [node, color, debug_line(node)]
        end
        # Named colors
        value.scan(/(^|\s)([a-z]+)(?=\s|$)/i) do |_, color|
          SassExtractor.color_nodes << [node, color, debug_line(node)] if Sass::Script::Value::Color::COLOR_NAMES[color] && color != 'transparent'
        end
      end

    protected

      def debug_line(node)
        "#{engine.filename}:#{node.line}: ( #{engine.lines[node.line - 1][0..-2].gsub(/\s+/, " ")} )"
      end

    end
  end

  class ColorExtractor
    def self.report(glob)
      gather_config = {
        'linters' => {
          'VariableGatherer' => { 'enabled' => true },
          'ColorGatherer'    => { 'enabled' => true }
        }
      }
      runner = SCSSLint::Runner.new SCSSLint::Config.new(gather_config)
      runner.run Dir.glob(glob)

      report_lines = []
      report_lines << "---------------------"
      report_lines << "Possible duplicates:"
      SassExtractor.color_nodes.each do |arr|
        next unless arr.is_a? Array
        duplicate_var = SassExtractor.color_var_nodes.select{|n| n.expr.value.to_s == arr[1].to_s }
        if duplicate_var.present?
          report_lines << "#{arr[2]} maybe should use $#{duplicate_var.map(&:name).join(' or $')}"
        end
      end

      report_lines << ""
      report_lines << "---------------------"
      report_lines << "Define Vars for:"
      SassExtractor.color_nodes.each_with_index do |arr, index|
        next unless arr.is_a? Array
        duplicate_var = SassExtractor.color_var_nodes.select{|n| n.expr.value.to_s == arr[1].to_s }
        if duplicate_var.blank?
          report_lines << "$var#{index}: #{arr[1].to_s}"
        end
      end

      report_lines << "---------------------"
      report_lines << "And use them here:"
      SassExtractor.color_nodes.each_with_index do |arr, index|
        next unless arr.is_a? Array
        duplicate_var = SassExtractor.color_var_nodes.select{|n| n.expr.value.to_s == arr[1].to_s }
        if duplicate_var.blank?
          report_lines << "#{arr[2]} should use $var#{index}"
        end
      end

      report_lines.join("\n")
    end
  end
end

module SCSSLint::LinterRegistry
  def self.linters
    [
      SassExtractor::Vistors::VariableGatherer,
      SassExtractor::Vistors::ColorGatherer
    ]
  end
end


# Run with
# puts SassExtractor::ColorExtractor.report(Rails.root.join 'app/assets/stylesheets/**/*.css.scss')