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How to have more than one type of cell in a Collection View

Published on: May 19, 2020

Collection views in iOS are awesome. You can use them to build complex custom layouts and since iOS 13 you can use Compositional Layouts to quickly build good looking layouts that would take forever to accomplish on iOS 12 and below. But what if you want to use more than one type of cell in […]

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What is type erasure in Swift? An explanation with code samples

Updated on: January 7, 2025

Swift’s type system is (mostly) fantastic. Its tight constraints and flexible generics allow developers to express complicated concepts in an extremely safe manner because the Swift compiler will detect and flag any inconsistencies within the types in your program. While this is great most of the time, there are times where Swift’s strict typing gets […]

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Getting started with testing your Combine code

Published on: May 11, 2020

A question that often comes up when folks get into learning Combine is “how do I test code that uses Combine?”. In this week’s post, I will briefly explain the basics of testing Combine code. I will assume that you already know the basics of testing and Combine. If you’re just getting started with both […]

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Creating type-safe identifiers for your Codable models

Updated on: April 5, 2021

Note: After publishing this article, it has been brought to my attention that the folks from @pointfreeco have a very similar solution for the problems I outline in this post. It’s called tagged and implements the same features I cover in this post with several useful extensions. If you like this post and plan to […]

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Why your @Atomic property wrapper doesn’t work for collection types

Published on: April 20, 2020

A while ago I implemented my first property wrapper in a code base I work on. I implemented an @Atomic property wrapper to make access to certain properties thread-safe by synchronizing read and write access to these properties using a dispatch queue. There are a ton of examples on the web that explain these property […]

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Changing a publisher’s Failure type in Combine

Published on: April 15, 2020

One of Combine’s somewhat painful to work with features is its error mechanism. In Combine, publishers have an Output type and a Failure type. The Output represents the values that a publisher can emit, the Failure represents the errors that a publisher can emit. This is really convenient because you know exactly what to expect […]

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An introduction to Big O in Swift

Published on: April 13, 2020

Big O notation. It’s a topic that a lot of us have heard about, but most of us don’t intuitively know or understand what it is. If you’re reading this, you’re probably a Swift developer. You might even be a pretty good developer already, or maybe you’re just starting out and Big O was one […]

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Using Closures to initialize properties in Swift

Updated on: April 23, 2024

There are several ways to initialize and configure properties in Swift. In this week’s Quick Tip, I would like to briefly highlight the possibility of using closures to initialize complex properties in your structs and classes. You will learn how you can use this approach of initializing properties, and when it’s useful. Let’s dive in […]

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How to use SF Symbols in your apps

Published on: April 6, 2020

It’s been a while since Apple announced SF Symbols at WWDC 2019 and I remember how excited everybody was about them. The prospect of having an easy to integrate set of over 1,500 icons that you can display in nine weights sounds very appealing and has helped me prototype my ideas much quicker with good […]

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Find and copy Xcode device support files

Updated on: October 13, 2020

Every once in a while I run into a situation where I update my iPhone to the latest iOS before I realize I’m still using an older version of Xcode for some projects. I usually realize this when Xcode tells me that it "Could not locate device support files". I’m sure many folks run into […]

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