Book Image

Mastering JavaScript Design Patterns - Second Edition

By : Simon Timms
Book Image

Mastering JavaScript Design Patterns - Second Edition

By: Simon Timms

Overview of this book

With the recent release of ES-2015, there are several new object-oriented features and functions introduced in JavaScript. These new features enhance the capabilities of JavaScript to utilize design patterns and software design methodologies to write powerful code. Through this book, you will explore how design patterns can help you improve and organize your JavaScript code. You’ll get to grips with creational, structural and behavioral patterns as you discover how to put them to work in different scenarios. Then, you'll get a deeper look at patterns used in functional programming, as well as model view patterns and patterns to build web applications. This updated edition will also delve into reactive design patterns and microservices as they are a growing phenomenon in the world of web development. You will also find patterns to improve the testability of your code using mock objects, mocking frameworks, and monkey patching. We’ll also show you some advanced patterns including dependency injection and live post processing. By the end of the book, you'll be saved of a lot of trial and error and developmental headaches, and you will be on the road to becoming a JavaScript expert.
Table of Contents (5 chapters)

Chapter 5. Behavioral Patterns

In the last chapter we looked at structural patterns that describe ways in which objects can be constructed to ease interaction.

In this chapter we'll take a look at the final, and largest, grouping of GoF patterns: behavioral patterns. These patterns are ones that provide guidance on how objects share data or, from a different perspective, how data flows between objects.

The patterns we'll look at are as follows:

  • Chain of responsibility
  • Command
  • Interpreter
  • Iterator
  • Mediator
  • Memento
  • Observer
  • State
  • Strategy
  • Template method
  • Visitor

Once again there are a number of more recently identified patterns that could well be classified as behavioral patterns. We'll defer looking at those until a later chapter, instead keeping to the GoF patterns.

Chain of responsibility

We can think of a function call on an object as sending that object a message. Indeed this message passing mentality is one that dates back to the days of Smalltalk. The chain of responsibility...