Function is_null

3rd/nlohmann_json/single_include/nlohmann/json.hpp:20052–20055

! @brief return whether value is null This function returns true if and only if the JSON value is null. @return `true` if type is null, `false` otherwise. @complexity Constant. @exceptionsafety No-throw guarantee: this member function never throws exceptions. @liveexample{The following code exemplifies `is_null()` for all JSON types.,is_null} @since versio

    @since version 1.0.0
    */
    constexpr bool is_null() const noexcept
    {
        return m_type == value_t::null;
    }

    /*!
    @brief return whether value is a boolean