Book Image

Mastering JavaScript Functional Programming - Second Edition

By : Federico Kereki
Book Image

Mastering JavaScript Functional Programming - Second Edition

By: Federico Kereki

Overview of this book

Functional programming is a paradigm for developing software with better performance. It helps you write concise and testable code. To help you take your programming skills to the next level, this comprehensive book will assist you in harnessing the capabilities of functional programming with JavaScript and writing highly maintainable and testable web and server apps using functional JavaScript. This second edition is updated and improved to cover features such as transducers, lenses, prisms and various other concepts to help you write efficient programs. By focusing on functional programming, you’ll not only start to write but also to test pure functions, and reduce side effects. The book also specifically allows you to discover techniques for simplifying code and applying recursion for loopless coding. Gradually, you’ll understand how to achieve immutability, implement design patterns, and work with data types for your application, before going on to learn functional reactive programming to handle complex events in your app. Finally, the book will take you through the design patterns that are relevant to functional programming. By the end of this book, you’ll have developed your JavaScript skills and have gained knowledge of the essential functional programming techniques to program effectively.
Table of Contents (17 chapters)
Technical Requirements

Behaving Properly - Pure Functions

In Chapter 3, Starting Out with Functions – A Core Concept, we considered functions as the key elements in Functional Programming (FP), went into detail about arrow functions, and introduced some concepts, such as injection, callbacks, polyfilling, and stubbing. In this chapter, we'll have the opportunity to revisit or apply some of those ideas. We will also do the following:

  • Consider the notion of purity, and why we should care about pure functions—and impure functions as well!
  • Examine the concept of referential transparency.
  • Recognize the problems implied by side effects.
  • Show some advantages of pure functions.
  • Describe the main reasons behind impure functions.
  • Find ways to minimize the number of impure functions.
  • Focus on ways of testing both pure and impure functions.