Function flatten

src/include/nlohmann/json.hpp:4725–4730

@brief return flattened JSON value @sa https://json.nlohmann.me/api/basic_json/flatten/

    /// @brief return flattened JSON value
    /// @sa https://json.nlohmann.me/api/basic_json/flatten/
    basic_json flatten() const
    {
        basic_json result(value_t::object);
        json_pointer::flatten("", *this, result);
        return result;
    }

    /// @brief unflatten a previously flattened JSON value
    /// @sa https://json.nlohmann.me/api/basic_json/unflatten/