The book is broken into two parts. The first part explains how object oriented programming concepts work in JavaScript and how to implement the ones that aren’t built into the language, such as interfaces and private members. The second part of the book focuses on a common set of design patterns and how they can be implemented in JavaScript. It covers the following patterns, giving a chapter on each one: Singleton, Factory, Bridge, Composite, Facade, Adapter, Decorator, Flyweight, Proxy, Observer, Command and Chain of Responsibility.

Before I go any further, while I’m going to write a mostly positive review for this book, I should say that I initially tried to read it around 18 months ago, but stopped after I finished the first section. I re-read it from start to finish about 2 months ago. I stopped the first time I tried to read it because the book introduces a lot of ideas and I was a little confused on some of the concepts it touched on. Specifically, I was confused with how constructor functions worked and how a function’s prototype property worked. I got distracted trying to understand this and picked up another book and ended up not coming back to this book (it’s hard for me to get back into a book once I’ve set it down for a while). As for constructor functions and the prototype property, a good explanation of them can be found here.

I had better luck on my second read through and found the second half of the book to be an easy read. Though each chapter focuses on a different design pattern, some of them use patterns introduced in earlier chapters, so it’s actually a good idea to read the chapters in order. Each of these chapters starts by explaining the basic idea behind the pattern and then goes into a couple of real world examples of how the pattern is used. The chapters close by discussing the benefits and drawbacks of the pattern they introduced and some advice is given to help you identify situations where using the pattern would be a good idea.

Overall, I found this be to be extremely interesting. I could possibly have learned about the different design patterns by reading online tutorials, but being able to look at solutions in JavaScript was very helpful. Also, after reading certain chapters, I felt like going back and rewriting some of my old apps (though I’ll contain myself). Knowing about this collection of design patterns is a huge plus for me and for that alone I’m glad I read this book. I wouldn’t recommend this book to someone who doesn’t have a good understanding of prototypal inheritance, but if you feel like you do, this book is worth checking out. If you don’t, I would recommend looking up some design pattern tutorials online and trying to learn about the common patterns, you’ll be glad you did.

On a side note, I was also amazed at how many of these patterns I’d seen before. It certainly gave me a better appreciation for some of the code bases I’ve seen in the past. I also found that I used some of the patterns already unknowingly, but that I didn’t have a name for the technique I was using.

If I could go back in time I would still probably take that Cryptology class, but I would also try and read up on Design Patterns too. If you have a few extra minutes, it’s worth reading up on them.

For those who don’t know, Ext JS is a JavaScript library aimed at helping developers create web applications with customizable user interface widgets. The library is known being sturdy and for letting users easily create eye-catching designs. However, unlike many other JavaScript libraries, Ext JS is licensed under the GPL by default. For people wanting to avoid the GPL, a commercial license can be purchased.

Ext JS 3.0 Cookbook is a book which has the goal of providing Ext JS users with a wide variety of techniques and code samples with which they can use in their development of web applications. The book is well written, has nicely formatted code samples (which are also available in a zip file – a URL to the file is given in the book), and contains a lot of interesting information. However, I wouldn’t recommend it to everyone, which I’ll get to in a moment.

Ext JS 3.0 Cookbook is divided into 10 chapters, with each chapter covering a different topic of the library. However, the book can really be thought of as one giant, categorized, FAQ guide on Ext JS. Each chapter contains a series of “recipes”. These recipes are specific tasks a developer might want to perform, for example: “Displaying remote data with a combo box” or “Creating a grid panel with expandable rows” or “Creating an auto-refreshing chart”.

The definition of each recipe follows a set pattern of 5 sections:

• The problem is described.
• “How to do it…” – Code for solving the problem is provided.
• “How it works…” – An explanation is given on how the code works.
• “There’s more…” – Additional, possibly useful, bits of information are provided.
• “See also…” – Other topics are suggested as further reading.

Each of these sections is given its own heading, though some recipes omit a section when it isn’t needed. This makes the book well suited as a reference guide since you know what you’ll be getting when you look something up. However, even though the book starts off with some recipes on working with the DOM and with data types, it’s not a book for Ext JS beginners. If you’re a new comer to Ext JS, you’re better suited by a book like Learning Ext JS.

Ext JS 3.0 Cookbook is really for those Ext JS users who are past the beginner stage and want something on-hand that will help them accomplish tasks they may run into or help them find better solutions to problems they’ve already had. If you work with the Ext JS library as part of your job or use the library a lot, having this book around would probably be beneficial. It’s nicely put together and has a lot of useful information. However, if you’re just a casual user of the Ext JS library, you’d probably find more benefit from an introductory text on the library or from just browsing their online documentation.