🚧 toward an ordered_json type

include/nlohmann/json_fwd.hpp

@@ -60,6 +60,19 @@ uses the standard template types.
 @since version 1.0.0
 */
 using json = basic_json<>;
+
+template<class Key, class T, class IgnoredLess, class Allocator, class Container>
+struct ordered_map;
+
+/*!
+@brief ordered JSON class
+
+This type preserves the insertion order of object keys.
+
+@since version 3.9.0
+*/
+using ordered_json = basic_json<nlohmann::ordered_map>;
+
 }  // namespace nlohmann
 
 #endif  // INCLUDE_NLOHMANN_JSON_FWD_HPP_