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

Producing Functions - Higher-Order Functions

In Chapter 5, Programming Declaratively  A Better Style, we worked with some predefined higher-order functions and were able to see how their usage lets us write declarative code so that we can gain in understandability as well as in compactness. In this chapter, we are going to go further in the direction of higher-order functions and develop our own. We can roughly classify the kinds of results that we are going to get into three groups:

  • Wrapped functions: These keep their original functionality while adding some kind of new feature. In this group, we can consider logging (adding log production capacity to any function), timing (producing time and performance data for a given function), and memoization (this caches results to avoid future rework).
  • Altered functions: These differ in some key points from their...