Swift

Reflection in Swift allows us to use the Mirror API to inspect and manipulate arbitrary values at runtime. Even though Swift puts a lot of emphasis on static typing, we can get the flexibility to gain more control over types than you might expect. I've been planning to explore the ...

An app update-notifier promotes a new app update to your users. Using a notifier will get better adoption rates with several benefits, like dropping old APIs and better conversion rates. In this article, I'll demonstrate how to create your update-notifier without using any remote configuration. The latest update will be ...

Composition and inheritance are both fundamental programming techniques when working in object-oriented programming languages. You've likely been using both patterns in your code already, even though you might not know what they mean. Over the past ten years, I've often been using inheritance throughout my code. Although using inheritance often ...

Property Wrappers in Swift allow you to extract common logic in a distinct wrapper object. This new technique appeared at WWDC 2019 and first became available in Swift 5. It's a neat addition to the Swift library that allows removing much boilerplate code, which we probably all have written in ...

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 should give you an idea already how important concurrency ...

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 actors in Swift, I encourage you to read my article Actors in Swift: how 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 EXC_BAD_ACCESS error. At this point, it's time to start your journey into solving ...

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 well-known EXC_BAD_ACCESS. By understanding the differences between them, you'll learn how to solve ...

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 ...