Book Image

JavaScript : Functional Programming for JavaScript Developers

By : Ved Antani, Simon Timms, Dan Mantyla
Book Image

JavaScript : Functional Programming for JavaScript Developers

By: Ved Antani, Simon Timms, Dan Mantyla

Overview of this book

JavaScript is a high-level, dynamic, untyped, lightweight, and interpreted programming language and functional programming is a style that emphasizes and enables smarter code that minimizes complexity and increases modularity. It's a way of writing cleaner code through clever ways of mutating, combining, and using functions. And JavaScript provides an excellent medium for this approach. By learning how to expose JavaScript's true identity as a functional language, we can implement web apps that are more powerful, easier to maintain and more reliable. The java script: Functional Programming for JavaScript Developers course will take you on a journey to show how functional programming when combined with other techniques makes JavaScript programming more efficient. The first module Mastering JavaScript, stress on practical aspects of Javascript development like—Functions and Closures, Runtime debugging techniques, project layout, events and DOM processing, build tools, Object-oriented patterns, isomorphism—everything that a modern Javascript project would need. The second module, Mastering JavaScript Design Patterns - Second Edition, 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. This updated edition will also delve into reactive design patterns and microservices as they are a growing phenomenon in the world of web development. It will also show you some advanced patterns, including dependency injection and live post processing. The third module, Functional Programming in JavaScript, will help you to write real-world applications by utilizing a wide range of functional techniques and styles. It explores the core concepts of functional programming common to all functional languages, with examples of their use in JavaScript.
Table of Contents (6 chapters)

Chapter 10. Messaging Patterns

When Smalltalk, the first real object oriented programming language, was first developed, the communication between classes was envisioned as being messages. Somehow we've moved away from this pure idea of messages. We spoke a bit about how functional programming avoids side effects, well, much the same is true of messaging-based systems.

Messaging also allows for impressive scalability as messages can be fanned out to dozens, or even hundreds, of computers. Within a single application, messaging promotes low-coupling and eases testing.

In this chapter we're going to look at a number of patterns related to messaging. By the end of the chapter you should be aware of how messages work. When I first learned about messaging I wanted to rewrite everything using it.

We will be covering the following topics:

  • What's a message anyway?
    • Commands
    • Events
  • Request-reply
  • Publish-subscribe
    • Fan out
  • Dead letter queues
  • Message replay
  • Pipes and filters

What's...