How to change guard-coffeescript result directory?

Question

CoffeeScript

Guardfile has a block

coffeescript_options = {
  input: 'scripts/coffee',
  output: 'scripts/',
  patterns: [%r{^scripts/(.+\.(?:coffee|coffee\.md|litcoffee))$}]

}

guard 'coffeescript', coffeescript_options do
  coffeescript_options[:patterns].each { |pattern| watch(pattern) }
end

*.coffee is stored in scripts/coffee/
*.js should be stored in scripts/ but ends up in scripts/coffee/
How do I change the output directory?