What You Need
To follow along with this book, you’ll need the following:
A Mac running macOS Catalina (10.15) or later. Earlier versions might work, but they’re untested.
Xcode 12 or later. Xcode is the main development tool for iOS. You’ll need Xcode 12 or later for the tasks in this book. Since Combine was introduced with the iOS 13 SDK, Xcode 11 might work as well - but the code in this book was tested against Xcode 12. You can download the latest version of Xcode from Apple’s developer site here: apple.co/2asi58y
An intermediate level knowledge of Swift. This book teaches you how to write declarative and reactive iOS applications using Apple’s Combine framework. Combine uses a multitude of advanced Swift features such as generics, so you should have at least an intermediate-level knowledge of Swift.
If you want to try things out on a physical iOS device, you’ll need a developer account with Apple, which you can obtain for free. However, all the sample projects in this book will work just fine in the iOS Simulator bundled with Xcode, so a paid developer account is completely optional.