Swift is a powerful and intuitive programming language developed by Apple for iOS, macOS, watchOS, and tvOS app development. It is designed to be safe, fast, and expressive.
Swift Anti-Patterns Overview
Swift, despite being a modern and safety-focused language, still has common anti-patterns that can lead to bugs, performance issues, and maintenance problems. Here are the most important anti-patterns to avoid when writing Swift code.
Force Unwrapping Optionals
Force unwrapping optionals with !
can lead to runtime crashes. Use optional binding (if let
), nil coalescing (??
), or guard statements instead.
Implicitly Unwrapped Optionals
Implicitly unwrapped optionals (var name: Type!
) should be avoided when possible. Use proper initialization or lazy properties instead.
Massive View Controllers
Break up large view controllers into smaller, focused components using patterns like MVVM, Coordinator, or Clean Architecture.
Not Using Swift's Type System
Leverage Swift’s strong type system with enums, structs, and generics to make code safer and more expressive.
Overusing Singletons
Singletons create hidden dependencies and make testing difficult. Use dependency injection instead.
Not Using Result Type for Error Handling
Use Swift’s Result
type for clearer and more consistent error handling in asynchronous code.
Not Using Swift's Access Control
Use Swift’s access control modifiers (private
, fileprivate
, internal
, public
, open
) to hide implementation details and create clear APIs.
Capturing Self Strongly in Closures
Use [weak self]
or [unowned self]
in closures to avoid reference cycles and memory leaks.
Not Using Swift's Collection Features
Use Swift’s powerful collection methods like map
, filter
, reduce
, compactMap
, and flatMap
for cleaner, more expressive code.
Using Force Try
Avoid try!
as it can cause crashes. Use proper error handling with do-catch
blocks.
Not Using Swift's Property Observers
Use Swift’s property observers (willSet
and didSet
) to react to property changes automatically.
Not Using Swift's Error Handling
Use Swift’s throws
and do-catch
for error handling instead of returning nil or optional values.
Not Using Swift's Value Types
Use structs and enums (value types) for data that should have value semantics, and classes for reference semantics.
Not Using Swift's Lazy Properties
Use lazy
properties for expensive resources that might not be needed immediately or at all.
Not Using Swift's Protocol Extensions
Use protocol extensions to share behavior across types without inheritance.
Not Using Swift's Modern Concurrency
Use Swift’s modern concurrency features (async/await, actors, tasks) for cleaner asynchronous code.
Not Using Swift's Property Wrappers
Use property wrappers to encapsulate property storage and access patterns.
Not Using Swift's Result Builders
Use result builders (like SwiftUI’s ViewBuilder
) for declarative, composable code.