In software engineering, a design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern isn't a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations.
The design patterns can be broadly classified into 3 categories -
- Creational: Singleton.
- Structural: MVC, Decorator, Adapter, Facade.
- Behavioral: Observer, Memento
Of all the design patterns in iOS, MVC (Model-View-Controller) is considered to be of utmost importance.
To know more you can visit:-
- https://www.raywenderlich.com/160651/design-patterns-ios-using-swift-part-12
- https://www.raywenderlich.com/160653/design-patterns-ios-using-swift-part-22
This is my favourite blog. :)