Current iOS And Swift Practices

Goal

Keep Swift/iOS answers modern without turning the workspace into stale API documentation.

For version-sensitive recommendations, verify against official sources before presenting as current best practice.

Prefer:

Avoid relying only on memory for:

Prefer simple, testable Swift over clever abstractions.
Prefer structured concurrency over ad-hoc callback or detached-task patterns when the deployment target and codebase support it.
Keep UI state changes on the main actor.
Avoid recommending new APIs until deployment target and project constraints are known.
For SwiftUI, separate pure view composition from side effects and navigation/workflow coordination.
For testing, use the framework already adopted by the codebase unless the user explicitly asks about migration.

Apple positions Swift Testing as a modern option for unit tests in Xcode 16 and later.
XCTest remains relevant, especially for UI tests, performance tests, and existing test suites.
Do not recommend wholesale migration from XCTest unless the project constraints support it.

Observation can be adopted incrementally; do not assume a project can immediately replace all ObservableObject usage.
In SwiftUI code review, focus on data ownership, lifecycle, invalidation scope, navigation boundaries, and side effects.
Avoid introducing @StateObject, @ObservedObject, @State, or @Observable recommendations without first identifying ownership and deployment constraints.

SwiftUI documentation: https://developer.apple.com/documentation/swiftui
Observation migration: https://developer.apple.com/documentation/swiftui/migrating-from-the-observable-object-protocol-to-the-observable-macro
Swift Testing: https://developer.apple.com/documentation/testing
XCTest: https://developer.apple.com/documentation/xctest
Swift language: https://developer.apple.com/swift/