Four good books that can help boost your JavaScript skills – #programming #bookreview

Ready for some enlightenment that can boost your JavaScript programming skills?

O’Reilly recently has published four books that can help you move from basic JavaScript library user to confident, experienced developer. 

“JavaScript started out as a simple and approachable front-end scripting language,” the publisher notes. “It has matured into a true cross-platform environment targeted by the latest emerging languages, frameworks, and developer tools.” The four new JavaScript books can help you “[l]earn how you can get the ultimate in responsiveness and interactivity from JavaScript, whether you use it on the front-end or server-side.” 

The four books are: JavaScript Enlightenment and DOM Enlightenment, both by Cody Lindley; Learning from jQuery by Callum Macrae; and Testable JavaScript by Mark Ethan Trostler.

#

JavaScript Enlightenment
Cody Lindley
(O’Reilly – paperback, Kindle)

Short, clear code samples are the stars of this fine, informative book. And most of the code samples can be viewed, executed and modified online using file links provided for the jsFiddle.net website.

The book’s goal is “to give the reader an accurate JavaScript worldview through an examination of native JavaScript objects and supporting nuances: complex values, primitive values, scope, inheritance, the head object, etc.” Cody Lindley adds: “I intend this book to be a short and digestible summary of the ECMAScript 3 Edition specification, focused on the nature of objects in JavaScript.”

Lindley keeps that promise in his 147-page book. His code samples rarely span more than a half page, and his explanatory paragraphs also are taut and to the point.

For example: “In JavaScript, objects are king: Almost everything is an object or acts like an object. Understand objects and you will understand JavaScript. So let’s examine the creating of objects in JavaScript….An object is just a container for a collection of named values (a.k.a properties).” 

Lindley’s book covers six of the nine native object constructors that are pre-packaged with JavaScript. The six are: Number(); String(); Boolean(); Object(); Array(); and Function(). He skips Date(), Error(), and RegEx() “because, as useful as they are, grasping the details of these objects will not make or break your general understanding of objects in JavaScript.” But he does hope you will learn them later, on your own. 

“JavaScript,” he writes, is mostly constructed from just these nine objects (as well as string, number, and boolean primitive values.) Understanding these objects in detail is key to taking advantage of JavaScript’s unique programming power and language flexibility.”

 # 

DOM Enlightenment
Cody Lindley
(O’Reilly – paperback, Kindle)

If you work with JavaScript, you probably rely on a Document Object Model (DOM) library such as jQuery to help you handle HTML scripting. 

But you can script the DOM without a DOM library, using JavaScript. Cody Lindley shows how in this excellent guide aimed at two types of developers who have experience with JavaScript, HTML, and CSS.

“The first developer is someone who has a good handle on JavaScript or jQuery, but has really never taken the time to understand the purpose and value of a library like jQuery,” Lindley writes. “The second type of developer is an engineer who is tasked with scripting HTML documents that will only run in modern browsers or that will get ported to native code for multiple OSes and device distributions (e.g., PhoneGap) and needs to avoid the overhead (i.e., size or size versus use) of a library.”

He notes that “HTML documents get parsed by a browser and converted into a tree structure of node objects representing a live document. The purpose of the DOM is to provide a programmatic interface for scripting (removing, adding, replacing, eventing, and modifying) this live document.”

Much of his 161-page DOM Enlightenment  focuses on how to work in JavaScript with “the most common types of nodes…one encounters when working with HTML documents.” He purposefully has “left out any details pertaining to XML or XHTML.” And, to help keep the book small, he has “purposely excluded the form and table APIs,” but adds: “I can see these sections being added in the future.”

Lindley also imposes a key technical limitation on the “content and code in this book….” It was, he says, “written with modern browsers (IE9+, Firefox latest, Chrome latest, Safari latest, Opera latest) in mind.”  

In keeping with the goals of O’Reilly’s Enlightenment series, explanations are short and concise and code examples are kept small. Also, the code examples are available online and can be displayed, run, and modified at the jsFiddle.net website.

 Cody Lindley emphasizes that he is “not promoting the idea of only going native when it comes to DOM scripting….” He hopes, instead,  “that developers may realize that DOM libraries are not always required when scripting the DOM.”

#

Learning from jQuery
Callum Macrae
(O’Reilly – paperback, Kindle)

Some developers work comfortably with jQuery yet have only a modest understanding of JavaScript.

Callum Macrae’s concise, well-written new book is intended to help fill that gap. It is “targeted at developers who know jQuery, but who don’t feel comfortable in their JavaScript knowledge or would just like to know more.”

The 102-page book focuses on the JavaScript code that jQuery covers up. It offers five chapters and two appendixes, with many short code examples and other illustrations. Much of the code is available through a GitHub repo.

Chapter 1, “Event Handling,” explains how event handling works in JavaScript and notes that “[e]vents are the heart of pretty much all web applications….jQuery provides a suite of functions to make event handling considerably easier than in JavaScript alone.” But these functions “add overhead and remove control from you, the developer. For this reason, it is important to know how you can handle events without jQuery in pure JavaScript.”

Chapter 2 covers “Constructors and Prototypes.” Writes Macrae: “Constructors are a way of creating objects, and can be initiated via the new keyword. Prototypes are one of the more powerful features of JavaScript, and allow the developer to declare a method or property that all instances of an object will inherit.” The chapter also can “help you understand how jQuery works, as jQuery itself uses prototypes.” 

Chapter 3 deals with “DOM Traversal and Manipulation.” Macrae notes that “jQuery includes a number of functions that make working with the DOM a lot easier than with JavaScript alone, which can be pretty ugly. However, the functions provided by jQuery can be rather hefty (especially in older browsers), and it is often a lot faster to just use pure JavaScript. Therefore, it is important to know how to work both.”

Chapter 4, “AJAX,” covers jQuery’s AJAX functions and concedes that they “offer some significant improvements over the native JavaScript AJAX features, as they are a lot easier to use.” Macrae explains: “AJAX is the act of making an HTTP request from JavaScript without having to reload the page; you could think of it as an inline HTTP request.” The chapter shows some jQuery AJAX requests and how those AJAX requests are sent in JavaScript. The goal is to help you get better at debugging code and also realize that “it isn’t worth loading the entire jQuery library to send a few requests and nothing else….”

Chapter 5, “JavaScript Conventions,” explains some “common conventions that you can use to improve your JavaScript…such as making your code more readable by using comments and whitespace correctly, optimizing your code in order to improve performance, design patterns, and some common antipatterns (code that causes more problems than it solves.)”

 This book is not recommended for persons who have no jQuery or JavaScript experience. Still, Appendix A, “JavaScript Basics,” provides a 28-page introduction to JavaScript, starting at “Hello World!” Appendix B, meanwhile, describes several applications and websites that can help you improve your JavaScript knowledge.

 # 

Testable JavaScript
Mark Ethan Trostler
(O’Reilly – paperback, Kindle)

“You have to test your code,” Mark Ethan Trostler emphasizes, “so why not make the process as easy and painless as possible?”

That’s a very desirable goal. Yet, as he notes a few sentences later, “testing–especially JavaScript testing–is complicated.”

For example: “Client-side JavaScript is especially difficult to test properly, as we have very little control over the environment within which our code runs. Multiple operating systems, multiple versions of operating systems, multiple browsers, multiple versions of browsers, not to mention plug-ins, extensions, different languages, zoom levels, and who knows what else, all conspire to hinder the performance of our applications. These permutations slow down, break, crash, and eat our applications for lunch. It’s a jungle out there!”

Trostler, a software engineer who works in test at Google, says his book “attempts to bridge the gap between sane development practices and JavaScript. JavaScript is a weird little language.” And he has aimed his guide at “people who encounter JavaScript professionally. Beginning, intermediate, or guru-level developers are all welcome, as this book has something for everyone.”

His 250-page how-to guide is structured into eight chapters that “tackle testable code in several steps. First we will investigate complexity. Then we will look at an architecture choice that attempts to limit complexity and coupling. With that as our foundation,” Trostler continues, “we will move on to testing, both at the functional level and at the application level.” From there, he delves into: code coverage; integration, performance, and load testing; debugging; and using automation in tests.

 “Writing unit tests for client-side JavaScript can be daunting,” Trostler states. “That means too many people don’t do it. This is not OK…”

Testable JavaScript is well written and rich with code examples, screenshots, diagrams and other illustrations. Whether you write client-side or server-side JavaScript — or both — or you are trying to rework some legacy files, Mark Ethan Trostler’s text can help you learn how to better create and maintain testable code.

Si Dunn

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s