missing_keys

# File actionpack/lib/action_dispatch/journey/formatter.rb, line 108
        def missing_keys(route, parts)
          missing_keys = []
          tests = route.path.requirements
          route.required_parts.each { |key|
            if tests.key?(key)
              missing_keys << key unless /\A#{tests[key]}\Z/ === parts[key]
            else
              missing_keys << key unless parts[key]
            end
          }
          missing_keys
        end