Combining

comb10.swift

_ = dataProvider
    .decode(type: DummyDecodable.self, decoder: JSONDecoder())
    .map({ (decodable) -> String in
        return "The user is \(decodable.userName) and his id is \(decodable.userId)"
    })
    .sink(receiveCompletion: { completion in
        print(completion)
    }, receiveValue: { response in
        print(response)
    })
dataProvider.send(Data("{\"userName\":\"Alex\",\"userId\":1}".utf8))

Output: The user is Alex and his id is 1