How to always return an array in Vapor 3 and Fluent (even for single entity requests)

Question

I'd like to have an index controller function that returns an array of entities if no request parameter is set or a single entity if the id parameter is set. However, I'd like to always receive an array, in the latter case it just contains only one element.

Here's my function:

final class AddressController {
    func index(_ req: Request) throws -> Future<[Address]> {
        if let id = try? req.query.get(UUID.self, at: "id") {
            // THIS IS NOT WORKING...
            return Address.find(id, on: req)
        } else {
            return Address.query(on: req).all()
        }
    }
}

Answer 1

final class AddressController {
    func index(_ req: Request) throws -> Future<[Address]> {
        if let id = try? req.query.get(UUID.self, at: "id") {
            return Address.find(id, on: req).map {
                guard let address = $0 else { return [] }
                return [address]
            }
        } else {
            return Address.query(on: req).all()
        }
    }
}