iOS Interview Question (Part 9)

1. what is Vertical and Horizontal slicing in swift
2. Explain generics, protocol constraints, and type safety.
3. What is Property Observer? Write an example.

what is Vertical and Horizontal slicing in swift

🔹 1. Vertical Slicing (Feature-based Approach)

• Definition: Breaking the app into independent, self-contained features (end-to-end functionality).
• Focus: Each slice contains UI, business logic, and data for a specific feature.
• Goal: Deliver small, working features instead of layers.

🛠 Example (Vertical Slice: Login Feature)

A Login feature would contain:
1️⃣ UI Layer (LoginViewController.swift)
2️⃣ Business Logic Layer (LoginViewModel.swift)
3️⃣ Networking Layer (AuthService.swift)
4️⃣ Data Layer (UserModel.swift)

💡 Benefits:
✅ Encapsulation → Each feature works independently.
✅ Easier Testing → Unit tests cover individual features.
✅ Faster Development → Teams can work on features separately.

📌 Code Structure for Vertical Slicing

📂 Features
 ├── 📂 Login
 │   ├── LoginViewController.swift
 │   ├── LoginViewModel.swift
 │   ├──…