Function is_null

extern/json/json.hpp:20524–20527

@brief return whether value is null @sa https://json.nlohmann.me/api/basic_json/is_null/

    /// @brief return whether value is null
    /// @sa https://json.nlohmann.me/api/basic_json/is_null/
    constexpr bool is_null() const noexcept
    {
        return m_type == value_t::null;
    }

    /// @brief return whether value is a boolean
    /// @sa https://json.nlohmann.me/api/basic_json/is_boolean/