1. 5 tips for writing better
JavaScript
Nael El Shawwa
@naelshawwa
nael.elshawwa@gmail.com
http://about.me/naelshawwa

2. Why learn better JS?
Easy to hack things
Easy to learn bad habits
Rich web apps today heavily depend on JS
20,000 lines of JS

3. Tip # 1: Namespacing
function hello(){ var nael = {};
alert (“Hello”);
} nael.hello = function(){
alert (“Hello”);
};
Stop declaring global functions, minimize
global variables

4. Tip # 2: Events
<a onclick=”doSomething();”>
dojo.connect(link, "onclick", ui,
Do Something
ui.doSomething);
</a>
Don’t bind behaviour using markup attributes
remember no global functions?
harder to change behavior in a large app

5. Tip # 3: Pub Sub
startup: function(){
//some other startup code
//subscribe to the event we will get back from the app
dojo.subscribe("nael.controller.app.currentPosition",
this, this.eventHandlers.updateMapCenter);
//when Im done starting up, yell to the app controller
saying Im ready
dojo.publish("nael.controller.app.requests",
["getBrowserCoordinates"]);
},
Publish / Subscribe results in cleaner more
maintainable code

6. Tip # 4: Templating
<div class="infoWindowContainer" dojoattachpoint="infoWindow">
<h1>${title}</h1>
</div>
Don’t mix HTML with JavaScript
Keep your markup in HTML and load via ajax
ex. Dojo widget template system

7. Tip # 5: Decorating
var car = {};
car.drive = function(x){
this.position = this.position + x;
}
var flyingDecorator = {};
flyingDecorator.fly = function(x,y){
this.position = this.position + x;
this.height = this.height + y;
}
Combine objects together when needed, don’t
copy and paste new code into existing
objects

8. How to learn more?
http://www.crockford.com/ - Douglas
Crockford
High Performance JavaScript - Nicholas
Zakas
Use & read into jQuery, Dojo, YUI code bases