Book Image

Mastering JavaScript Functional Programming

By : Federico Kereki
Book Image

Mastering JavaScript Functional Programming

By: Federico Kereki

Overview of this book

Functional programming is a programming paradigm for developing software using functions. Learning to use functional programming is a good way to write more concise code, with greater concurrency and performance. The JavaScript language is particularly suited to functional programming. This book provides comprehensive coverage of the major topics in functional programming with JavaScript to produce shorter, clearer, and testable programs. You’ll delve into functional programming; including writing and testing pure functions, reducing side-effects, and other features to make your applications functional in nature. Specifically, we’ll explore techniques to simplify coding, apply recursion for loopless coding, learn ways to achieve immutability, implement design patterns, and work with data types. By the end of this book, you’ll have developed the JavaScript skills you need to program functional applications with confidence.
Table of Contents (22 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback
Connecting Functions - Pipelining and Composition
Answers to Questions


We already mentioned currying back in the Arrow functions section of Chapter 1, Becoming Functional - Several Questions, and in the One argument or many? section of Chapter 3, Starting Out with Functions - A Core Concept, but let's be more thorough here. Currying is a device that enables you to only work with single variable functions, even if you need a multiple variable one.


The idea of converting a multi-variable function into a series of single-variable functions (or, more rigorously, reducing operators with several operands, to a sequence of applications of a single operand operator) had been worked on by Moses Schönfinkel, and there have been some authors who suggest, not necessarily tongue in cheek, that currying would be more correctly named Schönfinkeling!

Dealing with many parameters

The idea of currying, by itself, is simple. If you need a function with, say, three parameters, instead of writing (with arrow functions) something like the following:

const make3 = (a, b...