Recent articles

Arrays in Swift can hold on to all kinds of data. A common desire developers have when they use arrays, is to remove duplicate values from their arrays. Doing this is, unfortunately, not trivial. Objects that you store in an array are not guaranteed to be comparable. This means that it’s not always possible to […]

When we write code, we write bugs. It’s one of the laws of the universe that we can’t seem to escape. The tools we have to discover, analyze and fix these bugs are extremely important because without good debugging tools we’d be poking at a black box until we kind of figure out what might […]

If you’ve ever written or used a function that accepts a closure as one of its arguments, it’s likely that you’ve encountered the @escaping keyword. When a closure is marked as escaping in Swift, it means that the closure will outlive, or leave the scope that you’ve passed it to. Let’s look at an example […]

One of Swift’s incredibly useful features is its ability to dynamically compute the value of a property through a computed property. While this is a super handy feature, it can also be a source of confusion for newcomers to the language. A computed property can look a bit strange if you haven’t seen one before; […]

You have probably seen and used a property list file at some point in your iOS journey. I know you have because every iOS app has an Info.plist file. It’s possible to create and store your own .plist files to hold on to certain data, like user preferences that you don’t want to store in […]

As soon as Swift was introduced, people were adding their own extensions and patterns to the language. One of the more common patterns was the usage of a Result object. This object took on a shape similar to Swift’s Optional, and it was used to express a return type that could either be a success […]

In Swift, we’re able to pass a KeyPath instead of a closure to certain functions. It’s what powers syntax like map(\.someProperty) which you might have seen before. In this post, we’ll compare what code looks like without KeyPaths as functions, and how passing a KeyPath as a function can simplify your code. // Swift 5.1 […]

Handling errors in Swift is done using a mechanism where functions specify their ability to throw errors. In modern Swift versions (6.0 and up), functions can even specify the type of the error that the function might throw. When we call a function that can throw, we use special syntax to either ignore the error […]

The ability to define custom subscripts in Swift is really powerful. It allows us to write very natural and concise code. Consider the following example of a Grid with a custom subscript: struct Grid { let items : [[GridItem]] subscript(x x: Int, y y: Int) -> GridItem? { guard !items.isEmpty, (items.startIndex…items.index(before: items.endIndex)).contains(x) else { return […]

A new Swift 5.2 feature is the ability to call instances of types as functions. Or, as the Swift Evolution proposal calls it “Callable values of user-defined nominal types”. The very short description of this feature is that it allows you to call instances of any type that has a callAsFunction method implemented as if […]