Summary

In this chapter, we have explored the Swift Standard Library, Dispatch, and a piece of Foundation with URLSession. You should now be comfortable with basic types, containers (such as dictionaries and arrays), modern enumeration, mapping, and reducing techniques. With Dispatch, you now have a good understanding of the differences between threads and queues, how serial and concurrent queues can be used to effectively make your programs more performant (but also unsafe), and ultimately, how to use synchronization techniques to organize the execution of your programs in a safe manner. Finally, we scratched the surface of the Codable protocols and applied them to URLSession in a generic way. This will allow you to write a type-safe client with excellent error handling and resilience against malformed responses.

Not all projects are written solely in Swift; many still share implementations with Objective-C. Now that you have a good grasp of the Standard Library, in the next chapter, we will look at all of the kinks and quirks involved with working in a mixed-code base.