This article has been archived, as it was published several years ago, so some of its information might now be outdated. For more recent articles, please visit the main article feed.
Using associated enum values to avoid state-specific optionals
Basics article available: EnumsUsing associated enum values is a super nice way to encapsulate mutually exclusive state info (and avoiding state-specific optionals).
// BEFORE: Lots of state-specific, optional properties
class Player {
var isWaitingForMatchMaking: Bool
var invitingUser: User?
var numberOfLives: Int
var playerDefeatedBy: Player?
var roundDefeatedIn: Int?
}
// AFTER: All state-specific information is encapsulated in enum cases
class Player {
enum State {
case waitingForMatchMaking
case waitingForInviteResponse(from: User)
case active(numberOfLives: Int)
case defeated(by: Player, roundNumber: Int)
}
var state: State
}

Swift by Sundell is brought to you by the Genius Scan SDK — Add a powerful document scanner to any mobile app, and turn scans into high-quality PDFs with one line of code. Try it today.