Feature Request - Add specifier for optionally parsing a field.

When parsing JSON, it is possible for a dictionary for example to be provided, or be NULL. It might be useful to have the option to detect NULL fields, and decide not to parse them if they are NULL. See example JSON below.

{"id":50919991711,"serialNumber":null,"owner":{"id":1344078314,"type":"User"},"created":"2019-12-03T02:49:36.457Z","updated":"2019-12-03T02:49:36.457Z"}

{"id":50920076429,"serialNumber":null,"owner":{"id":1344182127,"type":"User"},"created":"2019-12-03T02:52:36.14Z","updated":"2019-12-03T02:52:36.14Z"}

{"id":51542420781,"serialNumber":null,"owner":null,"created":"2019-12-14T17:20:50.357Z","updated":"2019-12-14T17:20:50.357Z"}

As shown, the first two have their owner fields filled in with information, but the other has it set to NULL. The behavior I am thinking of is similar to using the strstr function to detect if the key is NULL, but rather, built into the JSON parser as a feature.