Pimp my app! Part 2: From Swift 2 to Swift 4

In this article, I explain how I update my app to the latest Swift version.

Automatic migration from Swift 2 to Swift 4 is not available. Don’t worry you can still get some help and Xcode does quite a good job at hinting you in order to perform this update.

First thing to do after opening the project is to change the build setting SWIFT_VERSION to the latest Swift version (here Swift 4.2).

Then Xcode will flag compilation error, warn about deprecated stuff, just proceed and eliminate the problems one by one.

Once the code compiles and run in the simulator, you can continue by adopting the latest tools that Swift 4 provide, for example:

• the guard keyword can replace a bunch of nested let
• JSON handling has improved a lot, by using the Codable protocol

Also in 3 years, some new techniques have become popular, like MVVM (more on that latter), whereas some other have declined in popularity, like RxSwift (IMHO). That is why I see plenty of opportunities for refactoring this little app beyond just Swift migration.