Learn all about declarative asynchronous programming with Swift using the Combine framework!Writing asynchronous code can be challenging, with a variety of possible interfaces to represent, perform, and consume asynchronous work — delegates, notification center, KVO, closures, etc. Juggling all of these different mechanisms can be somewhat overwhelming. Does it really have to be this hard? Not anymore!With Apple’s introduction of the Combine framework in WWDC 2019, it is clear that Apple aims to position declarative and reactive programming in Swift as a long-term investment and a game-changer in how developers perform and compose pieces of asynchronous work, making it a must-have tool at your disposal. The introduction of Combine as a built-in framework in Apple’s ecosystem is promising news to developers who were interested in frameworks such as RxSwift or ReactiveSwift, but didn’t want the overhead of a third-party dependency; and while experience with either of the above could be useful, it is not a prerequisite for this book. You’ll learn everything from the ground up to become a true Combine master.