In Binge for iOS and tvOS we decided to use a custom Swift Property Wrapper to help us inject dependencies into classes and ensure even singleton-esque objects can be mocked in unit tests. — The Problem Supporting multiple products that each have iOS and tvOS counterparts would quickly become a nightmare without clearly defined rules about how shared code (both internal and third party frameworks) can be used and mocked in unit tests. …

Recently we been migrating our (many) in-house libraries from CocoaPods to Swift Packages. To get an overview of our progress I built a new tool and subsequently learnt a bunch of lessons in something new to me: dynamically loading Swift libraries at runtime! — This is a bit of a longer article, so to whet your appetite here’s a partial list of the things we’ll cover (sometimes in excruciating detail) :

Here’s a way you can define helper functions in Swift that are injected into your app at runtime for use whilst debugging — no LLDB-esque Python required! — Act I — Setting the scene Let’s say we are debugging an issue where the focused view has gone missing. In other words, we are looking for any UIView instance whose isFocused property is true. In this scenario, it’s helpful to us to set that view’s background color to a red so that we can easily…

What if you need to fix an issue caused by an iOS version newer than the Xcode version you are using? — With the release of iOS13 imminent, we’ve found some critical issues that can only be fixed by using new APIs only available via Xcode 11. However our project uses Xcode 10 — building from Xcode 11 introduces even more issues. …

I recently experienced async/await whilst working in JavaScript. Wouldn’t it be great if we could do the same in Swift! — URLSession provides an asynchronous interface where a closure is called once the abstracted network call has completed. We’re all familiar with this, and it has encouraged us to write our own network layers in a similar fashion. A typical network call might be defined as:

I was recently shown FluentValidation, a popular framework for object validation in .NET — I decided to re-write the framework in Swift. It works nicely… but should you use it? — Fluent Validation Here is the original .NET framework (and here is my version). The idea behind the framework is you can use “fluent” rules to validate the properties of an instance so as to determine whether the entire instance can be considered “valid” or not. Suppose you have a CustomerModel such as:

Recently there’s been an issue with Application Loader where it simply doesn’t allow you to sign in, so I did some poking around and figured out how to bypass the broken UI. — If you’ve tried to upload your app using Application Loader recently you may have encountered the sign-in screen loading briefly and then refusing to budge. There’s a few threads about it around the internet too, for example:

Many fellow developers dream of launching our own product, be it big or small. Over the years I’ve had many ideas (that couldn’t be monetized easily) — here’s what I learnt when I finally followed through with one of them. — This article contains some technical language — but anyone who has had involvement with iOS or macOS development in any way will understand what I’m talking about! Whilst working on an iOS app in Japan I was having trouble translating documentation. I would have to copy Japanese text to my…

Inevitably, the API you’re developing with isn’t fully functional when the sprint starts or you aren’t given user accounts that cover all the possible cases you need to handle. You could add a breakpoint in Charles and change the response every time… but read on for a better way! — Charles is a powerful tool for inspecting HTTP requests coming from your devices. I’m going to assume you’ve used Charles a bit before reading this article 😉