Learn more about Swift concurrency

Enabling Concurrency warnings in Xcode 16

Updated on: November 4, 2024

If you want to make sure that your code adopts Swift concurrency as correctly as possible in Swift 5.x, it’s a good idea to enable the Strict Concurrency Checking (SWIFT_STRICT_CONCURRENCY) flag in your project. To do this, select your project’s target and navigate to the Build Settings tab. Make sure you select All from the […]

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The difference between checked and unsafe continuations in Swift

Updated on: July 9, 2024

When you’re writing a conversion layer to transform your callback based code into code that supports async/await in Swift, you’ll typically find yourself using continuations. A continuation is a closure that you can call with the result of your asynchronous work. You have the option to pass it the output of your work, an object […]

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Migrating callback based code to Swift Concurrency with continuations

Updated on: October 16, 2024

Swift’s async/await feature significantly enhances the readability of asynchronous code for iOS 13 and later versions. For new projects, it enables us to craft more expressive and easily understandable asynchronous code, which closely resembles synchronous code. However, adopting async/await may require substantial modifications in existing codebases, especially if their asynchronous API relies heavily on completion […]

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Comparing use cases for async sequences and publishers

Updated on: April 24, 2024

Swift 5.5 introduces async/await and a whole new concurrency model that includes a new protocol: AsyncSequence. This protocol allows developers to asynchronously iterate over values coming from a sequence by awaiting them. This means that the sequence can generate or obtain its values asynchronously over time, and provide these values to a for-loop as they […]

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Understanding Swift’s AsyncSequence

Updated on: April 24, 2024

The biggest features in Swift 5.5 all revolve around its new and improved concurrency features. There’s actors, async/await, and more. With these features folks are wondering whether async/await will replace Combine eventually. While I overall do not think that async/await can or will replace Combine on its own, Swift 5.5 comes with some concurrency features […]

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Using async await in Swift to build an image loader

Updated on: July 4, 2025

Async/await will be the defacto way of doing asynchronous programming on iOS 15 and above. I’ve already written quite a bit about the new Swift Concurrency features, and there’s still plenty to write about. In this post, I’m going to take a look at building an asynchronous image loader that has support for caching. SwiftUI […]

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