Validate on inclusion within array of options OR be nil

Question

I have a model where I\'d like to restrict input for a field to either be nil or fall within a specified array of values. I can get the inclusion part working, but the all

Answer 1

I solved this by making the validates line look like this:

validates :preferred_language, inclusion: { in: LANGUAGE_OPTIONS + [nil] }

This way, I allow nil, but I don't change the constant I use in my view for feeding the collection of select options. I've since also prepended the array with an element '' so I don't have to explicitly include blank in my form input helper.