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WebOS is missing from your list..... http://www.openwebosproject.or...
and their HTML5 framework: http://enyojs.com/

This doesn't address your compile-to-JavaScript/type-safety issues but for a component-based approach to producing JavaScript apps, take a look at http://enyojs.com./

A flippant answer but it misses the point. As does the original article. It's true that writing performant mobile apps is hard. But it's always true that writing good code that has to perform in a constrained environment requires attention to performance and memory.

However, one thing that JavaScript libraries tuned for mobile provide is an optimized approach to common problems that are handled differently on different mobile browsers. The framework I use (and I wrote the book on it, literally) is Enyo. As a simple example, Enyo provides a number of scroll strategies that it choose from based upon the OS and even the version. Are you aware of all the bugs in the various versions of the Android browser? How about the bugs introduced in one version iOS and fixed in the next? Having a framework deal with the wildly different browser implementations so you can focus on actually, you know, writing an app is important.

The original article goes to great lengths to talk about GC and brings up the strawman of video streaming and image manipulation. If you want to do those on mobile today, go native. If you want JS as a front-end, use PhoneGap. Pick the right tool for the job. He then talks about pure programming performance. Tell me, how many apps do you have on your phone that are processor bound? I would guess almost all of them sit around and do nothing until you tap a button. Responsiveness is completely different from outright performance and it's completely possible to write rich, responsive apps in mobile using JavaScript.

It's worthwhile noting that all the jsFiddle samples have been fixed. I can assure you they did work at the time the book was published.

I do intend for the book to continue to grow as Enyo does (there will be a chapter soon on the forthcoming Enyo MVC addition, for example) and I will definitely fix the (very few) typos so the electronic versions are updated.

Now, having dispensed with those, I need to point out that Enyo: Up and Running was intended as an introductory text, not a reference book. The Enyo Web site (which is very good) should always serve as the reference. This book, I think, does exactly what it was intended to: Introduce the key features of Enyo and explain how the fit into the broader context of the framework. The first chapter of the book is intended to give the reader a flavor for the development process with Enyo and how certain concepts are applied. I think moving it later into the book would diminish the value in it.

Finally, some responses to specific comments: Regarding the unused parameter, this is an interesting question I struggled with a bit. JavaScript doesn't care if you provide the appropriate number of parameters and it doesn't care if you use them or not. As a teaching text, the book shows all possible parameters whether used or not so that the reader knows they are available. I could easily have left them out of the samples, but at the risk of hiding their availability. Regarding the uses of CSS, I decided to save styling using CSS until the chapter on styling so as to not confuse the issue. Break tags fit within the flow of the sample and show off how to use the 'tag' property. I don't see that they are 'wrong' in any way.

Enyo is a relatively new framework (in its open source form) but has a strong legacy from the webOS days, as others point out. I find it very useful and I think it neatly addresses the many shortcomings of producing cross-platform apps. JavaScript is ubiquitous and the deployment options mean you're not beholden to Apple, Google or any other provider. I urge you to check out Enyo, even if you're not interested in the book. There's a lot to like there.

ExEn a windows mobile xna converter to Android and iOS makes me really like Windows Mobile as a development platform.

What's wrong with developing on Enyo then?

Enyo was just released as open source, and is practically the same framework. It will even run on desktop browsers!

http://enyojs.com/

There's a new enyojs.com website, where you can read about Enyo and try out some example apps, as well as downloading the current version.