I am trying to figure out what options I have for testing the value types for returned JSON variables that may not be required depending on the input. For instance, I have a returned "description" variable that is not a required field. The value returned can either be a string type or null value. When writing my expect statements, I tried using the .to.be.onOf(['string', null]), but that doesn't work correctly for this use case. Is there something out there that would allow me to check that it is one of those two?