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

Some bad solutions

OK, how many ways can you think of, in order to solve our problem? Let's go over several solutions, and analyze their quality.

Solution #1 - hope for the best!

How can we solve the problem? The first solution may seem like a joke: do nothing, tell the user not to click twice, and hope for the best! Your page might look as Figure 2.1.

Figure 2.1. An actual screenshot of a page, just warning you against clicking more than once

This is a weasel way of avoiding the problem, but I've seen several websites that just warn the user about the risks of clicking more than once (see Figure 2.1) and actually do nothing to prevent the situation... the user got billed twice? we warned them... it's their fault! Your solution might simply look as the following code.

<button id="billButton" onclick="billTheUser(some, sales, data)">Bill me</button>

OK, so this isn't actually a solution; let's move on to more serious...