On the Internet, you can find plenty of SwiftUI tutorials that dive straight into building user interfaces without much consideration for underlying architectural principles.

While these examples can get you started, they often lead to a common pitfall: massive SwiftUI views, i.e., views that are hundreds or even thousands of lines long, brimming with disparate logic.

In this article, I will explain why massive views are a problem and introduce a robust approach to building modular SwiftUI views that are more reusable, easier to understand, and instantly previewable in Xcode.

Since the introduction of SwiftUI, the MVVM pattern has become more relevant than ever. Many developers believe this particular pattern aligns well with the SwiftUI data flow.

MVVM incorporates good ideas but also introduces problems due to varying interpretations of the pattern and its perceived rigidity.

In this article, we’ll explore how MVVM fits into SwiftUI, how to leverage its advantages, and how to navigate its challenges.

SwiftUI offers several mechanisms to pass data between views.

If it seems complicated to decide which data flow mechanism fits your particular situation, that’s because such decisions cannot be made in isolation.

However, when you keep an app’s architecture in mind, it becomes easier to make the correct choice.

Downloading files in Swift can be pretty straightforward, thanks to URLSession and URLSessionDownloadTask.

Moreover, tracking the progress of a download can be easily achieved with URLSessionDownloadDelegate.

However, SwiftUI apps often need to track the download progress of multiple files, complicating their networking architecture.

When you need to download or upload data in Swift, the URLSession class is the solution you should reach for.

URLSession handles the most common Internet protocols and allows you to:

• Group and optimize data transfers.
• Handle authentication, cookies, and caching.
• Pause, resume, or cancel a download.
• Download data in the background when your app is suspended.

Asynchronous sequences are a core feature of Swift concurrency. They allow you to process asynchronous events easily using simple for loops.

However, conforming to the AsyncSequence protocol to create an asynchronous sequence is not straightforward.

That’s where AsyncStream comes to the rescue, allowing you to easily create asynchronous sequences and quickly adapt old APIs to Swift concurrency.

AsyncImage is a convenient SwiftUI view that loads remote images using a URL. It’s especially useful in apps that interact with REST APIs since images are usually referenced using URLs in JSON data.

While Apple’s documentation might lead you to believe that AsyncImage caches the downloaded images, that is not the case. If you need image caching, you must implement your own custom solution.