nlohmann::json helper

helper.hpp

#include "json.hpp"
#include <optional>

using json = nlohmann::json;

namespace nlohmann {

// https://github.com/nlohmann/json/issues/1910#issuecomment-615843605
template <typename T>
struct adl_serializer<std::optional<T>> {
    static inline void to_json(json& j, const std::optional<T>& opt) {
        if (opt == std::nullopt) {
            j = nullptr;
        } else {
            j = *opt;
        }
    }

    static inline void from_json(const json& j, std::optional<T>& opt) {
        if (j.is_null()) {
            opt = std::nullopt;
        } else {
            opt = j.get<T>();
        }
    }
};

template <typename Json, typename T>
static constexpr inline void JSON_SET(const Json& j, const char* s, T& t) {
    if (j.contains(s)) {
        j.at(s).get_to(t);
    }
}

} // namespace nlohmann