class Webpacker::Compiler

def watched_files_digest
  files = Dir[*default_watched_paths, *watched_paths].reject { |f| File.directory?(f) }
  file_ids = files.sort.map { |f| "#{File.basename(f)}/#{Digest::SHA1.file(f).hexdigest}" }
  Digest::SHA1.hexdigest(file_ids.join("/"))
end