Code Review in Swift: What to Check and How to Give Feedback to Beginners

Code Review in Swift: What to Check and How to Give Feedback

Code review is not just a formal code check before merging. It is one of the most effective tools for improving code quality, spreading knowledge within the team, and preventing bugs. For beginner iOS/macOS developers, the review process often seems intimidating: "What if I miss a critical error?" or "How do I write a comment without offending a colleague?" In this article, we will break down exactly what to pay attention to when reviewing Swift code, and how to give feedback that is both useful and motivating.

What to Check in Swift Code: A Reviewer's Checklist

To make the review structured and effective, divide the check into several logical blocks. Start with a general understanding of the task, then move on to the details.

1. Architecture and Logic

The first and most important point — does the code solve the given task? Do not delve into style until you are sure the logic is correct.

• Meeting requirements: Check that the code does exactly what is described in the task or ticket.
• Correctness of algorithms: Are there any logical errors? For example, are conditions in if or guard mixed up?
• Handling edge cases: What happens if the array is empty, or a network request returns nil? The code should be robust.

// ❌ Bad: the case of an empty array is not consideredfunc firstElement(_ array: [Int]) -> Int {    return array[0] // Crash!}

// ✅ Good: safe extractionfunc firstElement(_ array: [Int]) -> Int? {    return array.first}

2. Type Safety and Working with Optionals

Swift is a language with strong typing, and its strength is safety. Make sure the code author does not abuse force unwrapping.

• Force unwrap (!): Only acceptable in cases where you are 100% sure the value is not nil (e.g., IBOutlet).
• Using Optional Binding: if let or guard let — the standard and safe way.
• IUO (Implicitly Unwrapped Optional): Try to avoid them; use regular Optionals instead.

// ❌ Bad: force unwrap without checkinglet url = URL(string: "https://example.com")!// If the string is invalid - the app will crash

// ✅ Good: safe initializationguard let url = URL(string: "https://example.com") else {    print("Invalid URL")    return}

3. Naming and Code Readability

Code is read much more often than it is written. Good names for variables, functions, and types are the key to project maintainability.

• Swift conventions: Use camelCase for variables/functions and PascalCase for types (struct, class, enum).
• Clarity of name: The name should describe the purpose. v is bad, userName is good.
• Boolean properties: Should start with is, has, can (e.g., isEnabled).

// ❌ Badlet a = fetchData()

// ✅ Goodlet userProfile = fetchCurrentUserProfile()

4. Performance and Memory Management

For iOS/macOS applications, it is critical to avoid memory leaks and unnecessary computations.

• Retain cycles: Check closures — do they capture self without [weak self] or [unowned self].
• Threading: All UI updates must happen on the main thread. Check if DispatchQueue.main.async is used.
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