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You're reading from Hands-On Design Patterns with Swift Master Swift best practices to build modular applications for mobile, desktop, and server platforms

Product type Paperback

Published in Dec 2018

Publisher Packt

ISBN-13 9781789135565

Length 414 pages

Edition 1st Edition

Languages

Swift

Tools

Foundation

Concepts

Design Patterns

Authors (3):

Giordano Scalzo

Florent Vilmart

Sergio De Simone

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Table of Contents (17) Chapters

Preface

1. Refreshing the Basics

2. Understanding ARC and Memory Management FREE CHAPTER

3. Diving into Foundation and the Standard Library

4. Working with Objective-C in a Mixed Code Base

5. Creational Patterns

6. Structural Patterns

7. Behavioral Patterns

8. Swift-Oriented Patterns

9. Using the Model-View-Controller Pattern

10. Model-View-ViewModel in Swift

11. Implementing Dependency Injection

12. Futures, Promises, and Reactive Programming

13. Modularize Your Apps with Swift Package Manager

14. Testing Your Code with Unit and UI Tests

15. Going Out in the Open (Source)

16. Other Books You May Enjoy

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The observer pattern

The observer pattern is used when many objects need to listen to changes in one or many other objects.

NotificationCenter is one of the oldest APIs in Foundation, available since macOS 10+ and iOS 2.0, and is used to implement the observer pattern quickly and safely. Using NSObject, it is also possible to use Key-Value Observing (KVO) to observe changes in objects.

In pure Swift, however, you will need to use a third-party object as the NotificationCenter in order to listen to change events. Swift also provides a simple observation mechanism that notifies you when local values are updated.

Event-based programming

Observation is a popular programming strategy that lets you derive the current state of your application from the events you're listening to. Instead of polling for new information, your program will listen to events or notifications in order to update its state.

This strategy is particularly suitable for decoupling event sources from their consumption part. However...