Class: ActiveSupport::JSON::Encoding::JSONGemCoderEncoder

::JSON::Coder.new(&ActiveSupport::Ractors.shareable_proc { |value, is_key|
  # Serialize non-String/Symbol keys via #to_s based on the key's own type,
  # mirroring the legacy `jsonify` encoder. (#as_json is intentionally not
  # consulted here: Time#as_json returns an ISO8601 String, yet the key must
  # still be emitted via #to_s for backward compatibility.)
  if is_key
    # Keep compatibility by calling to_s on non-String keys
    if Symbol === value
      next value # Symbol#to_s needlessly allocate a string.
    else
      next value.to_s
    end
  end

  json_value = value.as_json

  # Handle objects returning self from as_json
  if json_value.equal?(value)
    next ::JSON::Fragment.new(::JSON.generate(json_value))
  end
  # Handle objects not returning JSON-native types from as_json
  count = 5
  until JSON_NATIVE_TYPES.include?(json_value.class)
    raise SystemStackError if count == 0
    json_value = json_value.as_json
    count -= 1
  end
  json_value
}).freeze

[Hash, Array, Float, String, Symbol, Integer, NilClass, TrueClass, FalseClass, ::JSON::Fragment].freeze