Functional JavaScript

Chapter 1. Introducing Functional JavaScript

This chapter sets up the book in a number of important ways. In it, I will introduce Underscore and explain how you can start using it. Additionally, I will define the terms and goals of the rest of the book.

The Case for JavaScript

The question of why you might choose JavaScript is easily answered in a word: reach. In other words, aside from perhaps Java, there is no more popular programming language right now than JavaScript. Its ubiquity in the browser and its near-ubiquity in a vast sea of current and emerging technologies make it a nice—and sometimes the only—choice for portability.

With the reemergence of client-service and single-page application architectures, the use of JavaScript in discrete applications (i.e., single-page apps) attached to numerous network services is exploding. For example, Google Apps are all written in JavaScript, and are prime examples of the single-page application paradigm.

If you’ve come to JavaScript with a ready interest in functional programming, then the good news is that it supports functional techniques “right out of the box” (e.g., the function is a core element in JavaScript). For example, if you have any experience with JavaScript, then you might have seen code like the following:

[1, 2, 3].forEach(alert);
// alert box with "1" pops up
// alert box with "2" pops up
// alert box with "3" pops up

The Array#forEach method, added in the fifth edition of the ECMA-262 language standard, takes some function ...