JavaScript: The Good Parts 1st Edition

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

I love the concept: Javascript is a diamond in the rough. Discard the rough and you will be working with a diamond.

I also like the concrete advice: the parts of Javascript to use, the parts to discard, and the parts to beware of.

I also like the explanations: how and why the good parts work. But this is where I begin to have reservations about the book. Some of the explanations are incomprehensible because of poor editing. How is it possible that a collection of technology pace-setters (Crockford, O'Reilly, Amazon) can leave numerous "confirmed serious technical mistakes" in their work uncorrected for at least 4 years (I bought it in 2012)?

O'Reilly's errata website for this book lists 157 'confirmed' errata, of which 9 are classified as "Serious Technical Mistake." There are also 22 "unconfirmed errata." Most of the confirmed errata were marked as fixed shortly after publication, but at least one of them ("beget") is still in the Kindle edition. O'Reilly helpfully provides downloadable copies of the example code online, but the current version still contains errors that prevent the code from running (mode/node).

I keep going back and re-reading this book, so looking past all my wasted time trying to make sense of the errors, I would give a correctly edited edition of this book five stars for the educational insights sprinkled through it. Or maybe not any more. The state of the art has changed. For example, as many one-star reviewers point out, the whole section on Object.create is outdated. This book needs a rewrite.

For me this book is perfect.

I have a lot of experience developing production applications using C/C++ in the past. I started learning JavaScript and found it easy to get started with. The online tutorials do a good job of exposing the syntax and basic concepts. Javascript is not interpreted C/C++, I found that it more resembled LISP the way it was used. I was definitely confused by the language (what is with all this function within a function stuff?) and I wanted to understand how the language works (literally how it is implemented).

Douglas clarified the concepts for me and now I feel more confident understanding how to use JavaScript. Also, he points out some major pitfalls, e.g. understanding how Arrays work is key to using them.

This book is NOT for beginners to programming.
This book is very opinionated on what the core language constructs are and how to use them and avoid the other parts.
This book is small but quite dense. I must have re-read some sections 5-6 times along with gathering other sources and running through some online examples. Probably depends on your background and level of experience with JavaScript but the concepts were pretty new to me.
Chapters 4&5 really get to the meat of JavaScript.
The book is an excellent reference and recommend owning it if you want to do serious programming with JavaScript.

Also, you can find Crockford on youtube quite easily. I went through his excellent series here: https://www.youtube.com/watch?v=JxAXlJEmNMg&list=PL7664379246A246CB

Enjoy!

Update: Note: I have purchased 3 O'Reilly books in the last couple of months. Each one of them has literally fallen apart. I will be reading a page and the page will come out of the binding. I am fairly gentle on the books so I think there is a binding problem at O'Reilly.