In this video course we will build goals app in SwiftUI 3 and iOS 15. We will build this app from start to finish and while building out this app you will learn about various design techniques and design patterns. You will learn to structure your code for enterprise level applications. You will also learn to build repository by following repository design pattern. We will follow protocol oriented programming to create repository protocol and pass generic protocol around so we can dependency inject strong repository at the time of app launch or while testing the app. This will make our app more flexible and will make unit test app much easier as mock repository will server the same purpose for unit tests as firebase repository will. This pattern will also allow you to build new repository(maybe for core data) at any time and swap it with firebase or mock repository.