quick graphql implementation for grape gem

json.rb

module Grape
  module Formatter
    module Json
      class << self
        def call(object, _env)
          
          only = _env[Grape::Env::RACK_REQUEST_QUERY_HASH]["__only__"]
          if object.respond_to?(:to_json)
            return only.present? ? object.to_json(only: only) : object.to_json
          end
          
          
          MultiJson.dump(object)
        end
      end
    end
  end
end

# a  = [:id, jobs: [:id, country: :id]].to_query('__only__')
# => "__only__%5B%5D=id&__only__%5B%5D%5Bjobs%5D%5B%5D=id&__only__%5B%5D%5Bjobs%5D%5B%5D%5Bcountry%5D=id"

# http://localhost:9292/bundles/68?__only__%5B%5D=id&__only__%5B%5D%5Bjobs%5D%5B%5D=id&__only__%5B%5D%5Bjobs%5D%5B%5D%5Bcountry%5D=id