Q1You assign a struct value to a new variable and mutate the copy. The original is:Swift Language
Q2Which is the safest way to handle a value that may be nil?Swift Language
Q3What prevents a strong reference cycle between two class instances?Swift Language
Q4Swift 6's headline change is:Swift Language
Q5In ForEach, using the array index as id can cause:SwiftUI
Q6Which wrapper marks state OWNED by the current view?SwiftUI
Q7The advantage of @Observable over ObservableObject is:SwiftUI
Q8.padding().background(.red) vs .background(.red).padding() differ because:SwiftUI
Q9What does awaiting an async call do to the thread?Concurrency
Q10To protect a mutable cache accessed by many tasks, you'd use:Concurrency
Q11Code that updates the UI should run on:Concurrency
Q12async let is used to:Concurrency
Q13Where should an authentication token be stored?Data & Networking
Q14To map JSON full_name to a Swift property fullName you can:Data & Networking
Q15SwiftData is best described as:Data & Networking
Q16The biggest build/structure win for a large app is usually:Architecture
Q17Injecting an APIClient protocol into a view model primarily improves:Architecture
Q18Before optimizing, you should:Performance
Q19A janky image feed most often improves when you:Performance
Q20A provisioning profile ties together:CI/CD & Tooling
Q21CFBundleVersion (build number) must:CI/CD & Tooling
Q22A phased release lets you:App Store
Q23App Transport Security (ATS) by default:Security
Q24A key benefit of on-device ML (Core ML) over a server call is:On-Device AI
Q25`some View` (an opaque return type) means the function returns:Swift Language
Q26To pass measured size from a child UP to an ancestor you use:SwiftUI
Q27Actor reentrancy means that across an await inside an actor method:Concurrency
Q28AsyncStream is most commonly used to:Concurrency
Q29Compared with a plain dictionary, NSCache automatically:Data & Networking
Q30A headline feature of StoreKit 2 is:App Store
Q31Public-key pinning protects against:Security
Q32Feature flags primarily let you:Architecture
Q33To run a third-party trained model on iOS you typically:On-Device AI
Q34Which framework gives you on-device text embeddings for semantic search?On-Device AI
Q35A home-screen widget's content is:SwiftUI
Q36An app and its widget share stored data through:Data & Networking
Q37To respect Dynamic Type you should:SwiftUI
Q38The Neural Engine's role is to:On-Device AI
Q39For a dynamic number of concurrent child tasks you should use:Concurrency
Q40Task.detached is discouraged by default because it:Concurrency
Q41Blocking a cooperative-pool thread with synchronous I/O is bad because:Concurrency
Q42The Clean Architecture dependency rule says dependencies point:Architecture
Q43Two feature modules need to navigate to each other. The clean fix is:Architecture
Q44Typed throws (Swift 6) let a function:Swift Language
Q45A 'hitch' refers to:Performance
Q46App Attest is used to:Security
Q47Changing a view's .id(value) causes SwiftUI to:SwiftUI
Q48Wrapping views in AnyView is discouraged because it:SwiftUI
Q49A shared-element 'hero' transition between two views is built with:SwiftUI
Q50The recommended implicit-animation modifier is:SwiftUI
Q51To animate a custom Shape's parameter, you implement:SwiftUI
Q52For a custom flow/tag arrangement that stacks can't express, you use:SwiftUI
Q53An app that is essentially a wrapper around your website is rejected under:App Store
Q54Unlocking digital content used in the app must use:App Store
Q55An app that lets users create an account must also:App Store
Q56If you offer Google/Facebook social login as a primary option, you must also offer:App Store
Q57Before accessing the IDFA / tracking across other companies' apps, you must:App Store
Q58A login-gated app submitted for review should include:App Store
Q59In StoreKit 2, you should grant an entitlement only when the transaction is:App Store
Q60The reliable source of truth for what a user currently owns on-device is:App Store
Q61Swift macros run:Swift Language
Q62@Observable and #Preview are, respectively:Swift Language
Q63A macro implementation depends on:Swift Language
Q64A type-safe reference to a property like \Type.name is a:Swift Language
Q65Mirror (reflection) is best described as:Swift Language
Q66The $ prefix on a property wrapper gives you its:Swift Language
Q67A Home Screen widget's content is best described as:SwiftUI
Q68Tapping a Button inside an iOS 17 interactive widget runs:SwiftUI
Q69For UI that must change while visible on the Lock Screen / Dynamic Island, use:SwiftUI
Q70In ActivityAttributes, the values you update over time live in:SwiftUI
Q71App Intents expose your app's actions to:SwiftUI
Q72To let an intent accept one of your model objects as a parameter, you implement:SwiftUI
Q73An icon-only button with no accessibilityLabel reads to VoiceOver as:SwiftUI
Q74Marking section titles with the .isHeader trait primarily helps users:SwiftUI
Q75To support Dynamic Type, you should mainly:SwiftUI
Q76Conveying success/error with color only is a problem because:SwiftUI
Q77The minimum recommended touch-target size is about:SwiftUI
Q78In XCUITest you should query elements by:Testing
Q79In Swift Charts, you build a chart from:SwiftUI
Q80To color/stack a bar chart by category you use:SwiftUI
Q81Bars can mislead if you don't set:SwiftUI
Q82iOS 17 tooltip selection is done with:SwiftUI
Q83With a 50k-point time series you should:Performance
Q84A donut chart in Swift Charts uses:SwiftUI
Q85In the iOS 17 SwiftUI Map, you add pins with:SwiftUI
Q86The blue user-location dot appears only when:SwiftUI
Q87As-you-type place suggestions use:Data & Networking
Q88Since iOS 14, a user may grant location that is:Security
Q89For low-power background location, prefer:Data & Networking
Q90A common App Review rejection around location is:Security
Q91Native WebSocket support comes from:Data & Networking
Q92To process a server token/event stream incrementally, use:Data & Networking
Q93Transfers that must continue when the app is suspended need a:Data & Networking
Q94Certificate pinning is implemented via:Security
Q95An ETag enables the server to respond with:Data & Networking
Q96On HTTP 429, the best first move is to:Data & Networking
Q97The device token for remote push is delivered to your app in:Data & Networking
Q98The preferred way for a server to authenticate to APNs is:Data & Networking
Q99To modify or decrypt a push before it's shown (e.g. attach media), use:Data & Networking
Q100A push with content-available: 1 and no alert is:Data & Networking
Q101An interruption level that breaks through Focus requires:Data & Networking
Q102A dev build's push token works against:Data & Networking
Q103Watch complications today are built with:SwiftUI
Q104iPhone↔Watch communication uses:Data & Networking
Q105A watch app can keep running in the background mainly during:SwiftUI
Q106Primary input on visionOS is:SwiftUI
Q107To call an iOS 17 API while supporting iOS 16, you use:Architecture
Q108The cleanest way to share logic across iOS/watchOS/macOS targets is:Architecture
Q109A camera capture pipeline is built around:Data & Networking
Q110To let users pick photos WITHOUT any library permission, use:SwiftUI
Q111Using the camera requires:Security
Q112Background audio + Lock Screen controls require populating:Data & Networking
Q113For real-time effects and mixing multiple audio sources, use:Data & Networking
Q114When processing camera frames you should:Performance
Q115To find out WHAT is mutating a variable, set a:Testing
Q116You should profile performance on:Performance
Q117Memory that's still referenced but never freed (e.g. an unbounded cache) is best found with:Performance
Q118A retain cycle is fastest to pinpoint with:Performance
Q119Function names in a production crash report require:Testing
Q120Which tool catches data races at runtime?Testing
Q121What does the actual drawing/compositing for a UIView?UIKit
Q122A shadow without a shadowPath is expensive because it causes:Performance
Q123shouldRasterize is a win for:Performance
Q124A callback synchronized to each display refresh comes from:UIKit
Q125You'd reach for Metal directly when:Performance
Q126Custom CADisplayLink animation on ProMotion should be:Performance
Q127If HealthKit read access is denied, your app:Security
Q128For a daily step-count total you'd use:Data & Networking
Q129To be woken when new health data arrives in the background, use:Data & Networking
Q130In HomeKit, the on/off state of a bulb is a:Data & Networking
Q131For stable device orientation you should read:Data & Networking
Q132Motion activity (walking/driving) classification requires:Security
Q133A CIImage represents:Data & Networking
Q134You should create a CIContext:Performance
Q135Chaining five CIFilters results in:Data & Networking
Q136To show many large photos without blowing memory, you should:Performance
Q137The modern way to render a UIImage off-screen is:Data & Networking
Q138For face detection today you use:Data & Networking
Q139SpriteKit is the right tool for:SwiftUI
Q140To make SpriteKit motion frame-rate independent, use:Performance
Q141In SpriteKit, to be notified when two bodies touch (without bouncing) you set:Performance
Q142RealityKit is architected around:Performance
Q143In ARKit, the rendering vs tracking split is:Performance
Q144To place an object where the user taps a real surface, use:Performance
Q145In Package.swift, a 'product' is:CI/CD & Tooling
Q146Bundled package resources are accessed at runtime via:CI/CD & Tooling
Q147What does a dependency rule of from: 1.2.0 allow?CI/CD & Tooling
Q148Local Swift packages mainly help by:Architecture
Q149Putting build settings in xcconfig files primarily:CI/CD & Tooling
Q150A custom Run Script phase that runs on every build (even when nothing changed) is missing:CI/CD & Tooling
Q151To let a user pick one contact WITHOUT a permission prompt, use:Data & Networking
Q152In iOS 17, an app that only adds calendar events should request:Security
Q153Before presenting MFMailComposeViewController you must:Data & Networking
Q154Why do the mail/message compose controllers need no special permission?Security
Q155Presenting UIActivityViewController on iPad requires:Data & Networking
Q156ShareLink can share any item that is:SwiftUI
Q157A user's own private CloudKit data is stored:Data & Networking
Q158To learn that CloudKit data changed without polling, use:Data & Networking
Q159Efficient incremental CloudKit sync relies on:Architecture
Q160A CloudKit save failing with serverRecordChanged means you should:Architecture
Q161For Core Data/SwiftData CloudKit mirroring, the model must have:Data & Networking
Q162Syncing a handful of small preferences across devices is best done with:Data & Networking
Q163In Combine, a publisher emits:Concurrency
Q164To debounce a search field in Combine you use:Concurrency
Q165Which subject replays its latest value to new subscribers?Concurrency
Q166To deliver values on the main thread for UI updates, add:Concurrency
Q167If you don't store the AnyCancellable from sink:Concurrency
Q168A Combine publisher can be consumed with async/await via:Concurrency
Q169To add one day to a Date you should:Swift Language
Q170The modern, locale-aware way to display a date is:Data & Networking
Q171You should store/transmit timestamps as:Data & Networking
Q172Hardcoding a date pattern like MM/dd/yyyy or a $ currency prefix is wrong because:Data & Networking
Q173Regenerable cached files should go in:Data & Networking
Q174Swift's native Regex (5.7) advantage over NSRegularExpression is:Swift Language
Q175A delegate property should be declared weak to:Architecture
Q176The main downside of using singletons for your services is:Architecture
Q177Dependency injection primarily improves:Architecture
Q178Lifting navigation out of view controllers into a dedicated object is the:Architecture
Q179To make impossible states unrepresentable, model state as:Architecture
Q180Wrapping a third-party SDK behind a protocol you own is the:Architecture
Q181The biggest single lever on pre-main launch time is usually:Performance
Q182To keep launch fast you should:Performance
Q183Launch prewarming means you should NOT assume:Performance
Q184What lets the App Store deliver only the assets/architecture a device needs?CI/CD & Tooling
Q185To shrink the initial download by deferring optional content, use:CI/CD & Tooling
Q186Your true per-device download size is shown by:CI/CD & Tooling
Q187In SwiftUI, a string literal passed to Text(...) is:SwiftUI
Q188The modern, auto-extracting localization format is:SwiftUI
Q189A sentence like You have 3 messages is best implemented with:SwiftUI
Q190Format strings with two arguments should use:Data & Networking
Q191For correct right-to-left mirroring you should use:SwiftUI
Q192Pseudolocalization helps you catch, before real translations:Testing
Q193To move focus between fields or dismiss the keyboard in SwiftUI, use:SwiftUI
Q194To surface an SMS one-time code in the QuickType bar, set the field's:SwiftUI
Q195Keyboard avoidance in SwiftUI is:SwiftUI
Q196Unhandled input/editing actions travel up the:UIKit
Q197To replace the system keyboard for a field with your own number pad, set:UIKit
Q198Reformatting text on every keystroke risks:SwiftUI
Q199Adding a .mlpackage to an Xcode project gives you:On-Device AI
Q200To run many inferences efficiently you should:On-Device AI
Q201A model runs partly on CPU even with .all because:On-Device AI
Q202Fine-tuning a model on the user's own data, privately, uses:On-Device AI
Q203To shrink a Core ML model you'd use coremltools to:On-Device AI
Q204Running an image classification Core ML model is easiest with:On-Device AI
Q205In Swift Testing, the macro that stops the test and can unwrap an optional is:Testing
Q206Running one test body over many inputs uses:Testing
Q207The TDD cycle is:Testing
Q208The cleanest way to mock a dependency in Swift is:Testing
Q209UI tests should locate elements by:Testing
Q210A common cause of flaky tests is:Testing
Q211SwiftUI drag and drop for your own typed payload uses:SwiftUI
Q212To reorder rows in a List you add:SwiftUI
Q213The currency for exchanging drag/drop data is:UIKit
Q214As the user hovers a drag over a UIKit target, the delegate returns a:UIKit
Q215Loading dropped data is asynchronous because:SwiftUI
Q216Good drag-and-drop UX should:SwiftUI
Q217some P (opaque) differs from any P (existential) in that some P:Swift Language
Q218A protocol with an associatedtype historically couldn't be used as:Swift Language
Q219some Collection<Int> (Swift 5.7) is enabled by:Swift Language
Q220Array is Equatable only when its Element is — this is:Swift Language
Q221A generic parameter used only for compile-time tagging (no stored value) is a:Swift Language
Q222In a hot path, prefer generics over `any` existentials because generics:Swift Language
Q223The single most important decision for an offline-first app is:Architecture
Q224A smooth image-heavy feed depends most on:Architecture
Q225Modeling checkout as a state machine helps by:Architecture
Q226Cross-feature navigation in a modular app without import cycles uses:Architecture
Q227The recommended way to migrate UIKit → SwiftUI is:Architecture
Q228You should add an extra layer or protocol when:Architecture