How Combine’s operators for connecting and merging publishers can be used to solve real-world problems, such as nested network calls, handling multiple input sources, and more.

This week, let’s explore the topic of published properties, by reimplementing Combine’s @Published property wrapper with support for earlier versions of Apple’s operating systems.

While there are a number of abstractions that we can create to be able to observe and communicate value changes — Swift comes built-in with a simple, yet powerful way to attach observations to any kind of non-lazy, stored property — appropriately named property observers.

Arguably one of the most challenging aspects of building apps for most platforms is making sure that the UI we present to the user always remains in sync with our underlying data models, and many techniques have been invented in order to address this problem. This week, let’s take a look at one such technique, that involves binding our model values to our UI.