Swift & SwiftUI Interview Prep – Senior iOS Developers

Here are some of the key questions that came up:

1. What are PassThroughSubject and CurrentValueSubject?
2. Explain Publisher and Subscriber.
3. Difference between @State and @Binding in SwiftUI.
4. What is AnyPublisher?
5. When do we use eraseToAnyPublisher?
6. What is AnyView?
7. What does the @Published property wrapper do?
8. Write a Combine pipeline to fetch data from two different network requests and output only when both complete. (💻 Live Coding Test)
9. What is a Cancellable?
10.Types of operators in Combine.
11. Usage of sink with completion.
12. Explain switchToLatest.
13. Build a 2-screen SwiftUI app (list + detail) that makes an API call using Combine only. (⏱️ 20-min Live Coding Test)
14. Difference between onReceive and onChange modifiers.
15. Coding Exercise:
👉 Given an array of strings, transform it into a new array:
Input → ["a", "b", "c"]
Output → ["c-0", "b-1", "a-2"]
⚡️ Requirement: Solve this using Swift higher-order functions such as map, enumerated, etc.

💡 If you’re preparing for iOS interviews, these are excellent questions to sharpen your fundamentals and practical skills in SwiftUI + Combine.

🤝 What other Swift / SwiftUI interview questions have you faced recently? Let’s share and learn together!