Bringing Polymorphism to Codable Polymorphism refers to the use of a single type to represent multiple different types. In this post, Matthaus Woolard shows us how to bring polymorphic behavior to Swift's Codable protocols, and provides a convenient property wrapper to avoid boilerplate code. Posted on May 14, 2021 | codable polymorphic
Introducing Swift Collections Like the Swift Algorithms package before it, the recently released Swift Collections package is intended to incubate new functionality for the Swift Standard Library. In this post, Karoy Lorentey from the Swift Standard Library team gives us a brief tour of what the package provides. Posted on May 14, 2021 | evolution open-source collection sequence
What’s the difference between a singleton and a shared instance in Swift? The Singleton pattern is a well-known design pattern that aims to allow exactly one single instantiation of a type. A similar pattern often used in iOS development is to create a shared instance of an object that can be accessed from anywhere in a project. In this short post, Donny Wals explains the subtle difference between the two. Posted on May 7, 2021 | singleton
Concurrency Done Right The Swift Concurrency Roadmap details future Swift language features which plan to make concurrent programming in Swift convenient and safe. However, there are already several ways we can add concurrency to our projects, and in this post, Alex Grebenyuk shows us how to do it right. Posted on May 4, 2021 | concurrency
Extending UIKit with Combine, MVVM and Unit Tests Apple's Combine is a powerful framework for processing values over time and is an alternative to popular frameworks such as RxSwift and ReactiveCocoa. In this short post, HammyAssassin shows us how to extend UIKit with Combine, creating a custom Publisher and Subscriber to respond to changes in a UITextField. Posted on April 27, 2021 | combine mvvm
The hidden cost of @testable Swift's @testable annotation affects how a module is imported, changing its access control to simplify testing. In this interesting post, Paul Samuels argues that there are hidden costs to using this feature. I don't entirely agree with everything Paul states, but it's always good to consider a different point of view. Posted on April 27, 2021 | testing
Using Combine’s futures and subjects Apple's Combine framework provides a declarative Swift API for processing asynchronous values over time. In this post, John Sundell demonstrates how some of Combine's convenience APIs can be used to wrap existing asynchronous APIs. Posted on April 23, 2021 | combine
Swift Result Builders: The Basics You Need to Know! Officially available in Swift 5.4, Result Builders is a Swift feature that enables functions to build up a result value from a sequence of components. In this post, Lee Kah Seng teaches us how this feature works, and how we can build custom Result Builders. Posted on April 13, 2021 | results builders
Custom Property Wrappers for SwiftUI A Swift property wrapper adds a layer of separation between code that defines a property and code that managers how a property is stored. By creating custom property wrappers, we write the management code once when we define the wrapper, and then reuse this code when we apply the wrapper to properties. In this post, Dave Delong shares some useful property wrappers that he has come up with while working on SwiftUI. Posted on April 12, 2021 | swiftui property wrapper
Why Swift closures are not Equatable Closures in Swift are reference types, and as such, we might assume that they are Equatable. However, that is not the case, and in this post, Jesse Squires digs into some old forum posts to help explain why. Posted on April 9, 2021 | compiler closure equatable