Composite in Swift
Composite is a structural design pattern that allows composing objects into a tree-like structure and work with the it as if it was a singular object.
Composite became a pretty popular solution for the most problems that require building a tree structure. Composite's great feature is the ability to run methods recursively over the whole tree structure and sum up the results.
Usage of the pattern in Swift
Usage examples: The Composite pattern is pretty common in Swift code. It's often used to represent hierarchies of user interface components or the code that works with graphs.
Identification: If you have an object tree, and each object of a tree is a part of the same class hierarchy, this is most likely a composite. If methods of these classes delegate the work to child objects of the tree and do it via the base class/interface of the hierarchy, this is definitely a composite.