How to implement pervasive features without sweeping changes — When developing an app, there are non-functional requirements that may affect the whole codebase. Consider logging, for example. To inspect an error, we could need to add logs in many different components to track the current state and what the user was doing. Different concerns share the same pervasive characteristic…

How to use generics and value types to reduce boilerplate in previews and other protocol implementations — One of the most annoying things in iOS development when working with UIKit is the slow feedback loop between implementing a piece of UI and seeing it on screen. When developing with UIKit, especially when working with code-first UI, we have to write all…

5 steps to develop any feature — There are many ways to develop a new feature. The process starts with a product owner coming to the dev team with an idea. They usually have some user research and some data to sustain the idea, and after a brief discussion, everyone agrees on building the feature. Then, the…

Thread-safe resources testing and actors — When working on big apps, we often need to share data among different components. Whether they are modules or just screens, they could need to read and write data from the same source. This introduces a problem: if the same date structure is used in different threads, we need to…

Use CoreData from an SPM package — Recently, I’ve been helping pro bono the Fight the Stroke association in maintaining and improving the MirrorHR iOS app. Fight the Stroke is a no-profit association whose goal is to improve the lives of families where there are children affected by cerebral palsy. MirrorHR…

How to keep your app state updated with SwiftUI views — Mutable state is the root cause of issues in several apps. It generates inconsistent states that lead to wrong displayed information or, in the worse case, to crashes. We face this problem when two different components use the same information with different representations and, if the user updates the information…

Handle multiple options in a generalized way — Sometimes, we face some interesting challenges that are worth sharing. These days, I was facing the issue of implementing a screen with multiple Yes/No options and a master switch that had to control all the children. I had to implement it in SwiftUI. At first, it looked like an easy…

Shortcomings of the default SwiftUI dependency injection mechanism — One of the main topics to master to create scalable and maintainable applications is Dependency Injection. SwiftUI comes with a comfortable API for injecting dependencies: the EnvironmentObject API, composed of a property wrapper and a view modifier. Despite these APIs being very comfortable, they have several limitations that make them…

Adapting your network layer to different interfaces — This year, Swift introduced the new async and await keyword. With them, we now have three ways to perform network operations: By using the old callbacks model By using Combine By using async-await In some cases, we make a decision early on one technology and we try to use it…