Empirical Study on Code Smells in iOS Applications

Code smells are recurring patterns in code that have been identified as bad practices. They have been analysed extensively in Java desktop applications. For mobile applications most of the research has been done for Android with very little research done for iOS. Although Android has the largest market share, iOS is a very popular platform. Our goal is to understand the distribution of code smells in iOS applications. For this analysis we used a collaborative list of open source iOS applications from GitHub. We combined code smells defined by Fowler and object oriented code smells studied on Android. We developed a tool that can detect these code smells in Swift applications. We discovered that iOS applications are most often affected by Lazy Class, Long Method and Message Chain code smells. Most often occurring code smells are Internal Duplication, Lazy Class and Long Method.