The most common Swift beginner mistakes and how to avoid them

Swift beginners often make the same mistakes. Most of them are not related to the complexity of the language, but to unfamiliarity with its philosophy of safety and strictness. Here are the 10 most common mistakes and how to avoid them.

1. Force unwrap (!) everywhere
   The most common and dangerous mistake. Instead of !, use if let, guard let, or nil-coalescing (??).
   
2. Ignoring optionals in collections
   Often write array[0] without checking if the array is not empty. Use first, last, guard let item = array.first else { return }.
   
3. Unnecessary use of var instead of let
   If the value does not change, always let. This helps the compiler and reduces the number of potential bugs.
   
4. Creating large Views in the body
   In SwiftUI, a large body is called frequently. Move complex logic to computed properties or separate Views.
   
5. Don't use @MainActor where you don't need to
   Updating UI from background threads causes crashes. Add @MainActor to ViewModel or use await MainActor.run.
   
6. Forget about weak/self in closures
   In functions that capture self, add [weak self] or [unowned self] (if you are sure that self is not nil).
   
7. Write everything in one file
   Even in small projects, separate into files: models, views, view models, services, etc.
   
8. Don't check for errors when working with the network
   Always handle do-try-catch or use throws-functions with async/await.
   
9. Use String instead of enum for states
   Instead of "loading", "success", "error", create an enum LoadingState with associated values.
   
10. Ignore compiler warnings
    Yellow warnings are not just recommendations. They often point to potential bugs (e.g. unused variables, deprecated APIs).

The best way to avoid these errors is to write code in small steps and refactor regularly. After each module, you should review your code and ask yourself: "Can I make this safer? Can I make it cleaner?"