Xcode Playgrounds do a lot more than run a snippet of Swift. Here’s what I found building a multi-page one: live views in SwiftUI and UIKit, image and color and audio and video assets, running XCTest without a test target, and a handful of things that took some testing to work out - so you don’t have to.
Unowned Self vs Others
What’s the real difference between Self, self, weak self, and unowned self in Swift? A hands-on look at closures, retain cycles, and ARC - with a playground to test it yourself.