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


6.1. A border case. What happens with our getField() function if we apply it to a null object? What should its behavior be? If necessary, modify the function.

6.2. How many? How many calls would be needed to calculate fib(50) without memoizing? For example, to calculate fib(0) or fib(1), one call is enough with no further recursion needed, and for fib(6) we saw that 25 calls were required. Can you find a formula to do this calculation?

6.3. A randomizing balancer. Write a higher-order function randomizer(fn1, fn2, ...) that will receive a variable number of functions as arguments, and return a new function that will, on each call, randomly call one of fn1, fn2, and so on. You could possibly use this to balance calls to different services on a server if each function was able to do an Ajax call. For bonus points, ensure that no function will be called twice in a row.

6.4. Just say no! In this chapter, we wrote a not() function that worked with boolean functions and a negate() function...