OrchardNest

Presentation tips can help you perform professional Swift talks by making sure you’re well prepared and professional-looking. Last week, I gave a talk at SwiftLeeds, and I realized all my experience from 5 years of talks at multiple...

SE-313 introduced the nonisolated and isolated keywords as part of adding actor isolation control. Actors are a new way of providing synchronization for shared mutable states with the new concurrency framework. If you’re new to...

Building apps all goes well in the beginning. You’re developing an app from scratch; it’s stable and runs perfectly fine. After releasing the first version, you get your first insights into crashes, from which one marks an...

Race conditions and data races are similar but have a few significant differences you should know. Both terms are often used when developing multi-threaded applications and are the root cause for several kinds of exceptions, including the...

The Thread Sanitizer, also known as TSan, is an LLVM based tool to audit threading issues in your Swift and C language written code. It was first introduced in Xcode 8 and can be a great tool to find less visible bugs in your code, like...

PassthroughSubject and CurrentValueSubject are two types from the Combine framework that conforms to the Subject protocol. Both are very similar but have a few keys differences that are important to know. You can see them as custom...

When a new iOS version arrives, it’s oftentimes a moment to reflect on the supported iOS versions and see to which minimum iOS version your project should be set. It’s an important decision in a developer’s job and not...

The @AppStorage Property Wrapper was introduced in SwiftUI to allow easy access to the user defaults. When property wrappers were introduced, many examples used a user defaults wrapper as an example. It’s a common use case where you...

Throwing properties allow defining computed properties that throw an error on failure. SE-310 introduced this feature in Swift 5.5 and is part of the async-await concurrency changes allowing async properties to throw errors. By defining...

Unwrap or throw is a scenario in which we want to throw an error if an optional returns a nil value. Techniques like if let or guard statements make this easy to do but often return in quite some boilerplate code. In cases like this,...

Async let is part of Swift’s concurrency framework and allows instantiating a constant asynchronously. The concurrency framework introduced the concept of async-await, which results in structured concurrency and more readable code...

Development Assets in Xcode allow you to provide test data to use within SwiftUI previews and other code during development. Assets marked for development will only be included in debug builds and removed once you create an archive of your...

Dependency Injection is a software design pattern in which an object receives other instances that it depends on. It’s a commonly used technique that allows reusing code, insert mocked data, and simplify testing. An example could be...

Async await is part of the new structured concurrency changes that arrived in Swift 5.5 during WWDC 2021. Concurrency in Swift means allowing multiple pieces of code to run at the same time. This is a very simplified description, but it...

MainActor is a new attribute introduced in Swift 5.5 as a global actor providing an executor which performs its tasks on the main thread. When building apps, it’s important to perform UI updating tasks on the main thread, which can...

Swift Actors are new in Swift 5.5 and are part of the big concurrency changes at WWDC 2021. Before actors, data races were a common exception to run into. So before we dive into Actors with isolated and nonisolated access, it’s good...

Flaky tests can be frustrating to deal with. You’re ready to open your PR until you realize your tests fail on CI while they succeeded locally. You even realize your test is succeeding when executing individually, and you’re...

Static Member Lookup is extended to Generic Contexts since the release of SE-0299. It might seem to be a minor change at first, but it allows simplifying quite some code. Especially if you’re writing your views in SwiftUI,...

WWDC 2021 introduced iOS 15 with many API changes, including improvements to presenting sheets in UIKit with the new UISheetPresentationController. iOS 14 already introduced the new sheet presentation style. Still, up until iOS 15, we...

WWDC 2021 is around the corner and will bring a ton of (home)work for all of us. A new Xcode, new APIs, SwiftUI improvements, and likely a lot more things we can’t predict. WWDC is often called “Christmas for iOS...

Swift jobs are something we’re all interested in if you’re reading my articles more often. Companies are hiring remotely more than ever since everybody is working from home either way and the request for new iOS and macOS apps...

Fileprivate and private are part of the access control modifiers in Swift. These keywords, together with internal, public, and open, make it possible to restrict access to parts of your code from code in other source files and modules. The...

Property Wrappers in Swift allow you to extract common logic in a distinct wrapper object. Since the introduction during WWDC 2019 and becoming available in Xcode 11 with Swift 5 there have been many examples shared across the community....

URLSession enables you to download and upload files while the app is in the background. Basic instructions to get it working are often found online, but it’s hard to make it work as expected and debug the flows. After implementing...

NSPredicate allows us to write predicates for validating a certain outcome. They’re often used combined with Core Data fetch requests and require a certain knowledge for writing custom formats. Besides my earlier shared Unit tests,...

Observing changes in Core Data NSManagedObject instances with Combine publishers can be a great solution to keep your user interface in sync with the latest changes. After reading through my posts in the Combine and Core Data categories,...

Conditional View Modifier creation in SwiftUI allows you only to apply modifiers if a certain condition is true. Whether it’s a simple checkbox value or an OS availability check, there are many cases in which you want to apply...

Combine was introduced as a new framework by Apple at WWDC 2019. The framework provides a declarative Swift API for processing values over time and can be seen as a 1st party alternative to popular frameworks like RxSwift and...

Optionals types in Swift either have a value or not, and there are several ways to test optionals using the XCTest framework. APIs like XCTUnwrap are designed to unwrap an optional and throw an error if unwrapping failed. However, it can...

Result builders in Swift allow you to build up a result using ‘build blocks’ lined up after each other. They were introduced in Swift 5.4 and are available in Xcode 12.5 and up. Formerly known as function builders, you’ve...

XCTExpectFailure was introduced in Xcode 12.5 and allows marking test failures as expected. The first time I read about this new API I was kind of confused: why wouldn’t we use methods like XCTAssertThrowsError instead? I continued...

A lazy var is a property whose initial value is not calculated until the first time it’s called. It’s part of a family of properties in which we have constant properties, computed properties, and mutable properties. A lazy...