NEW: Start my new Ultimate Portfolio App course with a free Hacking with Swift+ trial! >>

< Back to Latest Articles

Understanding assertions

In the full tutorial…

  • assert()
  • assertionFailure()
  • precondition()
  • preconditionFailure()
  • fatalError()
  • Where things get fuzzy…
  • Challenges
Get the full 27:33 video by subscribing

Already a subscriber? Log in here!

Why subscribe?


Hacking with Swift+ delivers high-quality tutorials for subscribers, with each tutorial coming as a 4K Ultra HD video and in text form so you can read or watch – whatever works best for you.

So, you can get this full video and article as well as all other subscriber-only tutorials and all future tutorials – all by subscribing to Hacking with Swift+ today.

Subscribe to Hacking with Swift+

Already a subscriber? Log in here!

More from Hacking with Swift+


How to use phantom types in Swift

24:11

ADVANCED SWIFT

FREE: How to use phantom types in Swift

Phantom types are a powerful way to give the Swift compiler extra information about our code so that it can stop us from making mistakes. In this article I’m going to explain how they work and why you’d want them, as well as providing lots of hands-on examples you can try.

Creating a WaveView to draw smooth waveforms

32:08

CUSTOM SWIFTUI COMPONENTS

FREE: Creating a WaveView to draw smooth waveforms

In this article I’m going to walk you through building a WaveView with SwiftUI, allowing us to create beautiful waveform-like effects to bring your user interface to life.

Using memoization to speed up slow functions

36:18

HIGH-PERFORMANCE APPS

FREE: Using memoization to speed up slow functions

In this article you’ll learn how memoization can dramatically boost the performance of slow functions, and how easy Swift makes it thanks to its generics and closures.

Shadows and glows

19:50

SWIFTUI SPECIAL EFFECTS

FREE: Shadows and glows

SwiftUI gives us a modifier to make simple shadows, but if you want something more advanced such as inner shadows or glows, you need to do extra work. In this article I’ll show you how to get both those effects and more in a customizable, flexible way.

Creating a custom property wrapper using DynamicProperty

14:20

INTERMEDIATE SWIFTUI

FREE: Creating a custom property wrapper using DynamicProperty

It’s not hard to make a basic property wrapper, but if you want one that automatically updates the body property like @State you need to do some extra work. In this article I’ll show you exactly how it’s done, as we build a property wrapper capable of reading and writing documents from our app’s container.

Ultimate Portfolio App: Introduction

14:17

ULTIMATE PORTFOLIO APP

FREE: Ultimate Portfolio App: Introduction

While I’m sure you’re keen to get started programming immediately, please give me a few minutes to outline the goals of this course and explain why it’s different from other courses I’ve written.

User-friendly network access

14:26

NETWORKING

FREE: User-friendly network access

Anyone can write Swift code to fetch network data, but much harder is knowing how to write code to do it respectfully. In this article we’ll look at building a considerate network stack, taking into account the user’s connection, preferences, and more.

Making the most of optionals

23:07

ADVANCED SWIFT

FREE: Making the most of optionals

Swift’s optionals are implemented as simple enums, with just a little compiler magic sprinkled around as syntactic sugar. However, they do much more than people realize, and in this article I’m going to demonstrate some of their power features that can really help you write better code – and blow your mind along the way.

Trees

31:55

DATA STRUCTURES

FREE: Trees

Trees are an extraordinarily simple, extraordinarily useful data type, and in this article we’ll make a complete tree data type using Swift in just a few minutes. But rather than just stop there, we’re going to do something quite beautiful that I hope will blow your mind while teaching you something useful.

Understanding generics – part 1

20:01

INTERMEDIATE SWIFT

FREE: Understanding generics – part 1

Generics are one of the most powerful features of Swift, allowing us to write code once and reuse it in many ways. In this article we’ll explore how they work, why adding constraints actually helps us write more code, and how generics help solve one of the biggest problems in Swift.

Making your app accessible

33:12

ULTIMATE PORTFOLIO APP

FREE: Making your app accessible

It is my firm belief that every iOS app should be usable to everyone, and putting in the work to make your app function well no matter who is using it says a lot about the kind of developer you are.

Creating a ShapeView to render UIBezierPaths

10:03

CUSTOM SWIFTUI COMPONENTS

Creating a ShapeView to render UIBezierPaths

Bezier paths let us draw all sorts of shapes efficiently and smoothly, and with a little work we can bring them into SwiftUI then animate them smooth, and in this article I’m going to walk you through making a very simple ShapeView struct to do just that.

Offering in-app purchases, part 1

51:56

ULTIMATE PORTFOLIO APP

Offering in-app purchases, part 1

Although many apps work great when paid for up front, many more work better when using a freemium model – you get lots of downloads of a free app, then charge for some kind of premium service. In this article we’re going to prepare to limit our app unless the user has paid for an unlock, but we’ll be using a flexible approach you can adapt easily.

Creating a FilteringList to filter a list using text input

27:34

CUSTOM SWIFTUI COMPONENTS

Creating a FilteringList to filter a list using text input

Many apps show lots of data in a list, and allow users to filter that list by typing in a text view. In this article we’re going to build that in SwiftUI, then pull it out into a reusable component you can apply anywhere.

The pros and cons of operator overloading

23:37

ADVANCED SWIFT

The pros and cons of operator overloading

I’ve written about operator overloading previously, not least in my book Pro Swift, but in the article I want to go into more depth on the places where it’s really useful – and the places where it’s not such a good idea.

Implementing App Clips in a real app

1:01:00

HACKING WITH SWIFT LIVE 2020

Implementing App Clips in a real app

Now that you understand how App Clips work, in this part we’ll apply them to our Barking Lot app so you can see them in action with real code.

Instant sync and save

16:31

ULTIMATE PORTFOLIO APP

Instant sync and save

Rather than calling update() when our view disappears, what we really want to do is update the object before the disappear happens. In this article I’ll show you the SwiftUI native way of doing this, then walk you through an alternative that I prefer.

Reading awards JSON

34:37

ULTIMATE PORTFOLIO APP

Reading awards JSON

Parsing data into your app is the single most common task any iOS developer needs to do, so in this article we’ll start to build out an Awards tab using JSON.

Uploading Codable data

27:13

NETWORKING

Uploading Codable data

In a previous article we already looked at a great way to download data using Combine, but in this article we’re going to examine the other side of the problem: uploading Codable data. Apple’s API here is a little gnarly, so I’m going to show you how to wrap it in a neat container using generics and Result.

Finding and fixing slow rendering

25:12

HIGH-PERFORMANCE APPS

Finding and fixing slow rendering

Instruments is a powerful tool for identifying performance problems, but in this article I’ll show you how to find code that slows down rendering in your app, causing slow scrolling, wasted CPU time, and more – all through the simulator.

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.