swift-coding-standards

Use capture lists with [weak self] in closures to break strong reference cycles, then call self optionally with self?.method(). Use [unowned self] only when self is guaranteed to outlive the closure, such as when the closure never escapes its owner.

Use structs for simple data models and value semantics where independent copies are desired, such as User or Point types. Use classes when you need shared mutable state, object identity, or inheritance, such as a singleton NetworkManager.

Install SwiftLint via Homebrew with brew install swiftlint, then add a build phase script running swiftlint. This Skill includes a .swiftlint.yml configuration with 30+ opt-in rules, line length limits of 120, and custom rules for weak self and force unwrapping.

Use weak when the referenced object can become nil during its lifetime, such as a delegate or parent view. Use unowned when the reference should never be nil after initialization, such as a CreditCard's customer, since accessing a deallocated unowned reference crashes.

Use withThrowingTaskGroup to execute multiple async operations concurrently. Add tasks with group.addTask for each operation, then collect results by iterating over the group, which runs all fetches in parallel instead of sequentially awaiting each one.

Yes, it covers SwiftUI MVVM architecture with @StateObject, @Published, and MainActor patterns, plus XCTest testing including mock objects, async test patterns, UI testing, and performance tests. Templates for ViewModel and TestCase files are included.