Returning some of a JSON array about argo

[gfontenot]

you could write your own parser to handle this. It would look a lot like the built in Array parser, but with catOptionals instead of sequence:

public func decodePartialArray<A where A: Decodable, A == A.DecodedType>(value: JSON) -> Decoded<[A]> {
  switch value {
  case let .Array(a): return catOptionals(A.decode <^> a)
  default: return .TypeMismatch("\(value) is not an Array")
  }
}

func catOptionals<T>(xs: [T?]) -> [T] {
    return xs.reduce([]) { accum, elem in
        return elem.map { accum + [$0] } ?? accum
    }
}

Then, in your decode function:

j <| "photos" >>- decodePartialArray

[tonyd256]

Yes, it's doable, but you might want to look into why you have partial information about a photo. If it's just because you're dealing with bad data that you don't have control over then that's one thing but if you do control that then fixing the data source to return full or no data for an image might be easier and more reliable.

[gfontenot]

You'll need to wrap that successful return statement in pure, too.

[sgoodwin]

Ah yes, that would work.

Tony: In this one case I have control over the API, but on most client projects I don't so I was curious.

Thanks again!