slice-to-json.cr

require "json"

struct Slice(T)
  def to_json(json : JSON::Builder)
    json.array do
      each do |e|
        e.to_json(json)
      end
    end
  end
end

empty = Slice(UInt8).empty
foo = Slice[1, 2, 3]

puts empty.to_json # => []
puts foo.to_json   # => [1,2,3]