Customer Reviews

JavaScript: The Good Parts

5 star:		(70)
4 star:		(19)
3 star:		(14)
2 star:		(9)
1 star:		(7)

 

 

Do you struggle when creating objects in Javascript?
Do you find the syntax to be non-intuitive and frustrating?
Do you know the difference between using a function as an object vs using an object literal?
Do you know how using object literals can simplify your code and create something similar to namespaces?
Do you know how to augment the type system -- for example, if wanted all strings to have a trim() method?
Do you know why the "new" statement is so dangerous? Do you know an alternative that eliminates the use of "new" entirely?

These are some of the topics that the book touches upon.

This book is aimed at someone with intermediate programming experience that wants to know the best way to create and use objects, arrays, types, etc. Crockford takes his experience with Javascript to show you best practices coding techniques and styles to use with Javascript. In addition, the book provides insights into what makes Javascript so confusing and what can be done about it.

You might ask "Isn't this stuff already covered in other books that I have?" The answer is no. For one, most other books use a psuedo-classical coding style (see below) to explain objects that is a source of confusion.

Javascript can be very confusing, especially for programmers who have extensive experience in other C-based languages (like myself). Writing good Javascript that uses objects, methods, etc. is hard. In Javascript, if you want to create objects, use inheritance and create methods, you have several different ways to write your code and it's difficult to know what the strengths and weaknesses of each are.

Crockford explains the problem plainly. Other C-based languages use class inheritance (Crockford calls this classical inheritance). Javascript, on the other hand, is the only popular language that uses prototype inheritance, which does not have classes. However, the syntax which Javascript uses to create object is Java-like (Crockford calls this pseudo-classical syntax). It's confusing, because it keeps you in a class-based frame of mind while working in a language that has no concept of classes.

Clarifying what's going on with the object model is the best part of this book. Crockford also explains other parts of Javascript that can be problematic and the techniques that he prefers for handling them. I don't necessarily agree with all of them, but the important thing is that he explains his reasoning.

To effectively learn Javascript, I recommend that you buy 1) a book that covers the details of the language and can be used as a reference (e.g. Javascript, the Definitive Guide) and 2) Crockford's book. Advanced programmers might also enjoy Pro Javascript Design Patterns, which shows a number of ways to combine Javascript with some of the GoF patterns. I would avoid any cookbook style books on Javascript, because you're better off using YUI, JQuery or one of the other Javascript libraries than writing your own drag-and-drops, calendars, etc.

There are a series of Yahoo! videos by Crockford that mirror the material in this book and can be found as podcasts under YUI Theater. They contain nearly all of the material in the book and probably a little more. Those videos are:

- Douglas Crockford/An Inconvenient API: The Theory of the DOM (3 parts)
- Douglas Crockford/The JavaScript Programming Language (4 parts)
- Douglas Crockford/Advanced JavaScript (3 parts)
- Douglas Crockford/Javascript The Good Parts

This is a beautiful book.

First of all - at only 170 pages it is short. Even though some of the key points are repeated through the book it's dense with information. You don't need any JavaScript experience, but it's not a "beginning programming" book so if you haven't been programming before this is not the right book for you.

Reading this book a couple of times will give you an appreciation for the JavaScript language that you almost certainly didn't have before. It'll give you tools to write better programs that you and others will actually be able to maintain over time.

I've learned lots of little things that I maybe knew from experience, but now I _know_ and I know why.

This book will help you battle with JavaScript rather than against it.

I'm a long-time C, C++, and Java programmer (videogames, predominantly) learning Javascript to do some web work, so I picked up this book because the reviews were good and the notion appealed to me - learn the subset of this rather sloppy language that you can use as a good language.

My TL;DR version of the review: this book is a hodgepodge of different information about the language, but some of it is so complicated it'll go immediately over the heads of new programmers, and then some of it is so mundane (even pedantic, talking about very specific aspects of coding styles) it felt goofy and out of place. It seems to me that any specific individual reading this book won't really find more than one or two chapters very relevant. I give it 3 stars because the useful parts were useful to me, but I skimmed and ignored 80+% of the book.

Crockford's writing is personable and clear, and the book's organization is straightforward. Here's my chapter-by-chapter breakdown. Note that this is all from my perspective, what I personally found useful or not, but my point is, while other readers will certainly disagree with me about what was useful, I have trouble imagining any one person finding more than about 20% of the book useful.

Chapter 1 is an introduction and high-level explanation of the point of the book.

Chapter 2 covers basic grammar and the likes, which was helpful though it's not aimed at any particular familiarity with other languages so it's trying to be comprehensive, which meant that as an experienced programmer in other languages I had to skim it and just look for differences with what I'm already used to.

Chapters 3 and 4 were the most useful parts of the book for me: the section on objects and functions, data scoping and closure, which really takes a new way of thinking if, like me, you have a lot of experience with languages without closure and anonymous functions and the like. Crockford does a good job of explaining this and giving relevant examples. This section was 20% of the book and was the only section I found really useful.

Chapter 5 covers inheritance. He presents two methods, one using new and constructors like one of the languages I'm more used to, and gives a couple reasons to avoid this, and then digs into the prototypal method, which is unfamiliar to me. The problem is that he uses totally abstract examples here - classes representing animals and methods that return their names or the noises they make - and it was very hard for me to relate it to any actual application, and since the prototypal style is a fundamentally different paradigm I don't feel like I really grasped it from his writing. Since he builds a framework of extension methods throughout the book, once I started to lost his train of logic I was utterly lost. And the "meta" nature of javascript, assigning functions to methods that return other functions that wrap functions, I found it easy to get lost.

Chapter 6 covers arrays. If you've used scripting languages this stuff is very simplistic, a stark change from Chapter 5, which is quite sophisticated. Again, my point here - I don't know who would simultaneously understand Chapter 5 and still find anything in Chapter 6 useful.

Chapter 7 is a significant change of direction; it's a long chapter on regular expressions which I skimmed very quickly since I know them from using perl. This part seemed odd, since regular expressions are common to several languages, and there's nothing particularly unique about javascript's usage of them. It felt a bit misplaced in this book. Certainly they're an important part of the language, but again made me wonder: who's the book for?

Chapter 8 is a reference for core API functionality and his extension methods; this feels like stuff I'd just google while coding, not terribly valuable to me personally.

Chapter 9 is a diversion on coding style, and felt wildly out of place and kind of insulting: if this book is for a seasoned programmer this is just going to trigger unpleasant flashbacks to arguments you had back when you were a junior programmer. If you're a new programmer and this stuff is news to you, other chapters in the book are going to be utterly incomprehensible to you.

Chapter 10, "The Beautiful Parts," is all of a page long, but a nice summary of the good aspects of the language.

Appendices A and B cover some of the "Awful & Bad Parts" of javascript in detail; this was the second-most interesting part of the book to me, though it's brief and you've picked it up if you read the rest of the book. Still, definitely value here. Though worth noting: he inserts some more editorializing here, ala Chapter 9 - he calls out some things that aren't specific to javascript, like switch statement fallthrough, as bad parts, which I found annoying. Stick to aspects unique to javascript and point out real dangers instead of offering advice on very broad aspects of coding style, I kept thinking.

Appendix C is about JSLint, the lint for javascript. It was useful only in the sense that I didn't know JSLint existed, and now I do, but then he gives a long swath of what amounts to JSLint documentation, which I have to imagine exists on the JSLint site, and felt like filler.

Appendix D is about JSON and just some reference information about the format. Maybe useful, but no authorial insight, just docs.

Overall, glad I read it, but I was pretty underwhelmed given the generally great reviews of the book on here.

Serious JavaScript programming requires strong discipline to avoid many pitfalls that are somewhat encouraged by the language itself. The author is very aware of this problem and wrote a small, but very dense book, full of useful advices that comes from somebody who has doing sophisticated JavaScript programming for a long time. Crockford is very opinionated, and I don't always agree 100% with his suggestions, nevertheless, even whenever I disagree, I find his points are worth reading, his opinion is always valuable. This book would serve well both veteran JavaScript developers and programmers that, coming from different languages, may get lost among JavaScript's idiosyncrasies.

Weighing in at 140+ pages of content, this book cuts through the obscurities, pleasantries, and filler found in most technical books. Instead, this book dives straight into the heart of the JavaScript language. It presents the clearest comprehensive explanation of what makes JavaScript a great programming language that I've encountered to date. It nails the important concepts, like JavaScript's: object oriented nature, its classless (pseudoclassical) nature, and functional nature. While covering the fundamentals like JavaScript's: functions, lexical scoping, lambdas, prototypal inheritance, and functional inheritance.

This book's size makes it approachable for all audiences, its style is terse and concise. This book has the potential to do for JavaScript, what Richie's inspirational classic the C Programming Language did for the C language.

JavaScript is the programming language of the web (AJAX), and this book will guide you through the good parts of this often misunderstood language - while this book is an excellent reference, it is not intended to replace JavaScript: The Definitive Guide, you'll do best to have both these books on hand.

If you enjoyed (or are considering) this book then you may want to hear more of what Douglas Crockford has to say, check out his great JavaScript video series on the YUI Theater.

I'm not sure what I thought this book would be; I guess I assumed it would be along the lines of "C Traps and Pitfalls". At times, however, it seems almost more like an essay.

Certainly, parts of the book are worth five stars. I was especially pleased to see the author's treatment of how null, undefined, and NaN all relate to one another in unexpected ways -- something that has puzzled me in the past. It was also good to see a list of the reserved keywords, some of which I didn't know before, and concrete examples of the dangers of == and != versus === and !==.

An unexpected treat was to read his discussions on the technical aspects and slowness of arrays, bitwise operators, and "with" statements in JavaScript, and the origins of "switch" in FORTRAN IV, and JavaScript's similarity to Lisp, despite its outward resemblance to C.

It was also bemusing to see his example of "flight.equipment && flight.equipment.model" on page 21, as I also learned that same lesson while working on a flight-related application.

Yet, for the head Javascript guy at Yahoo, it seems that a few things are missing. For example, while he does say on page 80 that slice() creates a shallow copy of an array, he does not make it explicitly clear that array2 = array1 will effectively create a pointer, i.e., a copy by reference. To make a truly independent copy of an array, one needs array2 = array1.slice() (no arguments necessary). This caused me a day of frustration when I first learned it.

And was it not Yahoo themselves that determined that scripts should come at the end of a web page to improve load speed? Why is that not in here?

We also have nothing about compression techniques.

On the web, for free, one can read Andy King's superb 2003 article on "Optimizing JavaScript For Execution Speed". And most of the discussion on objects can be learned much more succinctly and with better examples from MDC's "Core JavaScript 1.5 Guide".

One can learn a lot about download optimization from Dean Edwards.

Chapter 4 (Functions) was good; Chapter 2 (Grammar) did nothing for me.

I was also a little disappointed with Appendix B, "The Bad Parts". Most of this dealt with undisciplined programming as opposed to flaws with the language itself. E.g., "switch" statement fall-throughs are bad. Are they? If one of your people creates an unintentional fall-through, then deal with him; don't blame the language. Does Crockford also believe that firearms should be banned because of the potential of misuse, even though they have a valid purpose? How about steak knives? This is kind of like Edsger W. Dijkstra telling us that we can never use GOTO, even though it does have its place.

Further, I've used "continue" statements effectively, albeit not so often. Maybe I'm a bad programmer?

And then, he advises against autoincrements!! (++)

Regarding style, the book is definitely filled with the usual O'Reilly collegiate pompousness that's often good, sometimes not-so-good.

In summary, there are some good parts, but as a whole this is yet another pricey programming book from which I only needed 10 pages.

If you're at the plateau of understanding that it's actually the DOM that's slow and inefficient, and that Javascript is only guilty by association, and that it's actually an elegant little language, then there's probably something in this book for you.

This is an excellent book, as it concisely illustrates a number of details that would be impossible to find in other books. Moderate/advanced JavaScript programmers will gain the most from this book, it is not particularly geared towards the beginner.

The book has a very specific focus, so do not be deceived into thinking this book covers the entire language. For information like that, Flanagan's JavaScript The Definitive Guide will be better. This book, however, is an excellent discussion of the important features of the language. Highly recommended.

'JavaScript: The Good Parts' is a beautiful book that is a must-buy for all Javascript developers out there. Written with brevity clearly in mind (total is only a scant 150+ pages), this book will teach you how to become a BETTER Javascript developer and know why you want to do some things one way and avoid the pitfalls of doing things the WRONG way.

This book is all about efficiency and cleanliness. Written by one of the main developers of JSON, this book is organized smartly and craftfully. I love the fact that there isn't bloat and it's very easy to get through this book in no time at all. Does that mean you aren't getting your money's worth with this book??? HELLS NO!!

If you want to improve your Javascript developing skillset you owe it to yourself to pick up this book, it's one of the best books on the market in this subject matter.

***** HIGHLY RECOMMENDED

This is the first book by Douglas Crockford a Senior Software Archtitect at Yahoo. He is widely known as one of the most knowledgeable on JavaScript apart from the creater of JavaScript (Brendan Eich). Douglas Crockford is the creator of JSON and has written many articles and presentations on JavaScript-related topics in web development.

His book JavaScript: the Good Parts, is a short (145 pages including Appendix) but is very useful for the person who wants to expand his/her JavaScript skills and knowledge. It reviews the basics of the language in the first two chapters and then focus on intermediate and advanced topics such as objects, inheritance, arrays, and methods.

The appendix categorizes the "bad" parts of JavaScript that are not good programming syntax and should be avoided such as global variables, scope, eval function, with statement, undefined variables and so forth.

I really like how Douglas Crockford gives you everything you need in this book that is relevant to how modern developers using JavaScript program and helping you understand it easily and quickly. No long-winded explanations or extra "filler" just to make the book longer. He is right to the point and explains it in a coherent, understandable way no matter what your "technical" level is.

This is a very useful book for the client-side developer who wants either a great reference book or somebody who wants to take their skills to the next level using JavaScript.

A must buy!

This book has some good parts, even some great parts. Many parts of Chapters 3, 4, and 5 are very insightful, and might revolutionize how you think about Javascript, even programming in general. (Unless you come from a Lisp or functional programming background, in which case the insights will be old hat to you).

Unfortunately, the book as a whole seems to suffer from an identity crisis, or a lack of effort by the author to craft a consistent work, or perhaps a struggle between the author and publisher. Whatever the cause, it seriously compromised the quality and integrity of what could have been an amazing book. Instead of the tome of grand enlightenment that it should have been, we are left with a few gems buried amidst mounds of useless filler material.

The introduction explains that this is not a book for beginners, which is true, because beginning programmers would find most of Chapters 3, 4, and 5 to be completely impenetrable. Even experienced programmers may find them difficult to grasp. As the introduction says, this book is "small but dense," which is a nicer way of saying that it throws advanced techniques and code samples at the reader without sufficient explanation.

The introduction also explains that this is not a reference book, which is also true, because it does not describe the DOM at all, nor even list all the standard methods and functions built into Javascript. The introduction suggests that the reader should go look on the internet to find such references, which you'll certainly need to do if you plan to actually use Javascript for anything. But despite it not claiming not to be a reference book, the author decided in Chapter 8 to present a mishmash of standard methods, without any clear reason for why some are listed and others omitted, nor even a mention of the fact that there are others you should be familiar with.

And even though it is not a reference book or a book for beginners, a significant chunk of the book is spent explaining very basic concepts that the target audience is undoubtedly already familiar with. For example, 14 pages are spent explaining the syntax for whitespace, numbers, strings, if statements, while loops, and so on, all of which will be nothing new to anyone who has used C, C++, Java, etc. The book even provides railroad diagrams to illustrate each syntax, which adds thickness but little value to the book, then repeats them in Appendix D to add another 10 pages of pure bulk.

There is a lot of other filler material, as well, such as the appendix on JSLint, which is a slightly more polished copy of the documentation [...], and the appendix on JSON, which is a slightly more polished copy of the documentation [...], both being pet projects of the author. Neither of these appendices adds value to the book, only thickness.

If Crockford and O'Reilly were interested in offering a really great book, or even a book worth the price tag, they should have cut the filler, expanded the explanations where they are needed, and offered more insights and substantial practical examples.

But I can't really recommend the book as it is now, unless you buy it used or borrow it from a library. You would be better off with a Javascript beginner's guide plus reference to learn the basics, or proper guide to functional programming (regardless of the programming language) to learn the advanced techniques.