swift-ios-development

When to Use

• Building iOS, iPadOS, macOS, watchOS, or tvOS applications.
• Writing Swift code for any Apple platform or server-side Swift.
• Working with UIKit view controllers, Auto Layout, or navigation.
• Building declarative UIs with SwiftUI.
• Implementing async/await concurrency or reactive data flows.
• Writing unit or UI tests with XCTest.

Swift Language Patterns

Optionals — Null Safety

// guard let — preferred for early returns
func greet(name: String?) {
    guard let name = name else { return }
    print("Hello, \(name)")
}

// Optional chaining + nil coalescing
let length = user?.profile?.bio?.count
let displayName = user.nickname ?? user.fullName ?? "Anonymous"

Protocols and Extensions

protocol Repository {
    associatedtype Entity: Identifiable
    func findById(_ id: Entity.ID) async throws -> Entity?
    func save(_ entity: Entity) async throws
}

// Default implementations via extension
extension Repository {
    func findByIdOrFail(_ id: Entity.ID) async throws -> Entity {
        guard let entity = try await findById(id) else {
            throw RepositoryError.notFound(id: "\(id)")
        }
        return entity
    }
}

// Extend existing types
extension Date {
    var isToday: Bool { Calendar.current.isDateInToday(self) }
}

extension Array where Element: Numeric {
    var sum: Element { reduce(0, +) }
}

Enums with Associated Values

enum NetworkResult<T: Decodable> {
    case success(T)
    case failure(NetworkError)
    case loading
}

enum Route: Hashable {
    case home
    case userDetail(userId: UUID)
    case settings(tab: SettingsTab)
}

// Pattern matching
switch result {
case .success(let data):
    updateUI(with: data)
case .failure(let error) where error.isRetryable:
    scheduleRetry()
case .failure(let error):
    showError(error)
case .loading:
    showSpinner()
}

Generics

func fetch<T: Decodable>(from url: URL) async throws -> T {
    let (data, response) = try await URLSession.shared.data(from: url)
    guard let httpResponse = response as? HTTPURLResponse,
          (200...299).contains(httpResponse.statusCode) else {
        throw NetworkError.invalidResponse
    }
    return try JSONDecoder().decode(T.self, from: data)
}