My notes from "TheDeadline" presentations

Recently TheDeadline[1] presentations were[2] published[3] on Slideshare. I believe they have an incredibly powerful message about a modern style of web development using HTML5 and JavaScript. My notes from the presentations are in this post.

Rules of Modern Web development

1. You should be able to understand what your application does just by reading the code.

• Do not overuse JavaScript callbacks
• Don't call other callback functions from within a callback (Spaghetti)

2. Don't try to write Windows-style Desktop apps inside the browser.

• Begin with UX in mind, proceed with CSS3 and JavaScript
• De-couple formatting and display from content using CSS3

3. Be prepared to render most of your HTML code on the client-side.

• Server-side per component content generation doesn't scale, and is limited by the server boundary
• Consider Closure Templates[4] or Mustache[5] for templates - they work on both JavaScript and server-side

4. Don't write JavaScript in the style of the Java language. Forget everything you learned by writing Java code.

• No complex class hierarchies. JavaScript was not meant for this
• Write functional code
• Consider adopting Google Closure[6] -- Google Clojure Library is to JavaScript what the JDK is to Java

5. Plan ahead for Offline capabilities. But be aware, that users maybe try to sync stale data.

• Use local storage
• Use caching

6. You'll need an idea how to cope with concurrent modifications, when it is likely that your users can modify the same data at the same time and this could cause problems.

• Optimistic Locking
• While versioning data just store the actions as delta, not the snapshots. Gain? Real-time Analytics!

7. You need push notifications.

• Event-loop on the client side and a fast, async server-side REST API

8. Key/values != E-R model

• Use a persistence model that matches the app data model
• E-R is not it

9. Log client-side exceptions to the server.

• Wrappers that do this transparently
• Should gather enough context though

You can catch more of related stuff at their blog[7].

Links:
1. http://the-deadline.appspot.com/
2. http://www.slideshare.net/smartrevolution/using-clojure-nosql-databases-and-functionalstyle-javascript-to-write-gextgeneration-html5-apps
3. http://www.slideshare.net/smartrevolution/writing-html5-apps-with-google-app-engine-google-closure-library-and-clojure
4. http://code.google.com/closure/templates/
5. http://mustache.github.com/
6. http://code.google.com/closure/
7. http://www.hackers-with-attitude.com/

If you have feedback on this post, or any opinion on these topics, please let me know.