Book Image

Hands-On Design Patterns with Swift

By : Florent Vilmart, Giordano Scalzo, Sergio De Simone
Book Image

Hands-On Design Patterns with Swift

By: Florent Vilmart, Giordano Scalzo, Sergio De Simone

Overview of this book

Swift keeps gaining traction not only amongst Apple developers but also as a server-side language. This book demonstrates how to apply design patterns and best practices in real-life situations, whether that's for new or already existing projects. You’ll begin with a quick refresher on Swift, the compiler, the standard library, and the foundation, followed by the Cocoa design patterns – the ones at the core of many cocoa libraries – to follow up with the creational, structural, and behavioral patterns as defined by the GoF. You'll get acquainted with application architecture, as well as the most popular architectural design patterns, such as MVC and MVVM, and learn to use them in the context of Swift. In addition, you’ll walk through dependency injection and functional reactive programming. Special emphasis will be given to techniques to handle concurrency, including callbacks, futures and promises, and reactive programming. These techniques will help you adopt a test-driven approach to your workflow in order to use Swift Package Manager and integrate the framework into the original code base, along with Unit and UI testing. By the end of the book, you'll be able to build applications that are scalable, faster, and easier to maintain.
Table of Contents (22 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

Container types


Container types are data types that are useful for containing other types. We'll spend this section covering the most prominent features of the most widely known and used containers: 

  • Array
  • Dictionary
  • Set

Arrays are unordered collections of the same element; dictionaries are keyed collections of elements; sets are unordered collections of unique elements.

Arrays

Unlike in Objective-C, a Swift array can only hold elements of the same type, and it's a value type.

The following code declares an Array container of three Int types,  1, 2, and 3:

let ints = [1,2,3] // Array<Int> or [Int]

As an example, if you wanted them to be Doubles, you could easily force the type on it:

let doubles: [Double] = [1,2,3]

Mutability and operations

These arrays are immutable, as they are defined as let; it is therefore not possible to add or remove elements from them. Hopefully, we can still make mutable copies of them:

var otherDoubles = doubles
otherDoubles.append(4)
let lastDoubles = otherDoubles.dropFirst...