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

Dependency Injection, a primer


In this introductory section, we'll see what Dependency Injection is, where it comes, and how it's defined so that we can then discuss various methods to implement it, having a clear understanding of its principles.

We'll also see the benefits it brings to the software, the reasons to apply it, and when to do so.

What is Dependency Injection?

Dependency Injection is one of the most misunderstood concepts in computer programming. This is because the Dependency Injection borders are quite blurry and they could overlap with other object-oriented programming concepts. We'll start with a uniform definition of the DI so that we can proceed without confusion.

Definition

Let's start with a formal definition:

Note

"In software engineering, Dependency Injection is a software design pattern that implements inversion of control for resolving dependencies." - Wikipedia

To be honest, this is not really clear: what is Inversion of Control? Why is it useful for resolving dependencies...