Swift

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 data races. At WeTransfer, ...

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 can move boilerplate code into a wrapper. Although the @AppStorage wrapper is ...

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 throwing computed properties, we better handle unhappy flows without defining methods for simple accessors—the same ...

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, I'm always hoping to find ...

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 for asynchronous methods. If you're new to async-await, it's recommended first to read my article Async await in Swift ...

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 initializing a view with the network provider as a dependency. There are many ...

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 to understand what Data Races are and to ...

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, you're going to have fun adjusting your code for this new addition ...

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 didn't have the possibility to create an Apple Maps-like implementation of the sheet with a ...

Swift jobs are something we're all interested in. Companies are hiring remotely more than ever since everybody is working from home either way and the request for new iOS and macOS apps keeps on growing. As a Swift engineer, it's tempting to jump on a recruiter's message telling you about ...

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 private access level is the lowest and most restrictive level ...

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 background uploading support for Collect by WeTransfer myself, I decided ...