Recipe

Build a Recipe app using SwiftUI + Concurrency.

This iOS app displays a list of recipes with detailed information.
Recipes are grouped by category (cuisine) and sorted alphabetically, with a search feature.
Users can refresh the list via pull-to-refresh, and images are cached in both memory and disk for improved performance.

• iOS 16.0+

I focused on writing maintainable and testable code using a modern SwiftUI + Swift Concurrency approach. And implementing stable and efficient caching logic.

• Declarative UI design using SwiftUI
• Clean separation of concerns using View - ViewModel - Repository - Data Source layers
• Asynchronous programming with async/await
• Efficient use of concurrency and threading
• Custom image caching implementation (without third-party libraries)
• Dependency injection for maintainability and testability
• High test coverage
• Not bad UI and design...

I spent approximately 20 hours on the project during 5 days.

• UI: 30%
• Networking, caching, business logic: 50%
• Testing and refactoring: 20%

Time was also spent researching SwiftUI, Concurrency, and caching logic design.

• Download Management: Features like download cancellation (e.g., handling duplicate requests or canceling ongoing downloads) were not implemented. These would be important for improving stability and performance in a more complex app.
• LRU(LFU) Caching: LRU(LFU) caching would be a good option for better cache management, but it was a bit too complicated for this project. Instead, I used the file creation date as metadata to manage cache expiration.
• Design system: If there were a defined design system, I would have set up shared styles and components like fonts, colors, and common views. For this project, I kept things simple and handled them inline.
• Error handling: Just used print for error cases. In a production setting, I would log, handle, and categorize errors properly.
• Detail view: Current version only shows Site and YouTube link. With more time, I could embed the video or show full recipe information for better usability.

Initially considered but not implemented

• Pagination and prefetching: Due to the small dataset and endpoints don't support pagination.
• Search optimization: Did not use debouncing (Combine) since we do not call api during search.

• The image caching could be improved:
  • Memory cache is a singleton pattern. Simple but it may not be the optimal solution.
  • No cancellation or reuse of previous network requests.
• Reusable color, font, and view components
• Error handling could be more user-friendly.
• The search feature could be enhanced (e.g., history).

• Although not mentioned in the requirements, I implemented a custom memory caching to improve image performance.
• In addition, I added a simple expiration logic for the disk cache to make sure outdated files don’t stay in the cache over time.
• It was a valuable experience to build an image cache from scratch and verify its effectiveness using Xcode tools like Instruments and Debug Navigator.
• I really enjoyed working. It was a fun challenge and a great opportunity to learn more about SwiftUI, Architecture, and Caching.