Branching with Combine

BranchingWithCombine.swift

URLSession.shared.dataTaskPublisher(for: URL(string: BASE_URL + filename)!)
  .flatMap { data, response in
    let httpURLResponse = response as! HTTPURLResponse
    
    switch httpURLResponse.statusCode {
    case 404:
      return Just("Unable to find file").eraseToAnyPublisher()
    case (300..<399):
       // this is a function that returns a publisher - it can make network requests, whatever
      return processRedirect(data)
    case (200..<299):
      // now process data normally
    default:
      return Failure(errorType).eraseToAnyPublisher()
  }
  
func processRedirect(redirectData: Data) -> AnyPublisher<String, Error> {
   // ...
}