Access JavaScript Object Variable Properties
Not all JavaScript objects are as easy as MyObject.property. Sometimes you may want to access a property whose key is stored in a variable. Luckily accessing these properties is very easy.
Javascript Object Property Accessing Example
/* setting */
var myObject = {
left : 30,
top: 20
};
/* basic access */
var left = myObject.left; //OR
var left = myObject['left'];
/* accessing it or variables */
var mode = 'vertical';
var value = myObject[mode == 'horizontal' ? 'left' : 'top'];
You may use array-style syntax to access an object's properties. The string within brackets returns the properties.
![Regular Expressions for the Rest of Us]()
Sooner or later you'll run across a regular expression. With their cryptic syntax, confusing documentation and massive learning curve, most developers settle for copying and pasting them from StackOverflow and hoping they work. But what if you could decode regular expressions and harness their power? In...
![Creating Scrolling Parallax Effects with CSS]()
Introduction
For quite a long time now websites with the so called "parallax" effect have been really popular.
In case you have not heard of this effect, it basically includes different layers of images that are moving in different directions or with different speed. This leads to a...
![Add Site Screenshots for External Links Using MooTools Tooltips]()
Before you send your user to an unknown external website, why not provide them a screenshot of the site via a tooltip so they may preview the upcoming page? Here's how you can do just that using MooTools.
The MooTools JavaScript
The first step is to grab...
![Spoiler Prevention with CSS Filters]()
No one likes a spoiler. Whether it be an image from an upcoming film or the result of a football match you DVR'd, sometimes you just don't want to know. As a possible provider of spoiler content, some sites may choose to warn users ahead...
I’m a big fan of myObject[key] as its close to the PHP array syntax. Just personal preference really and it gives great flexibility and easy to test for.
@Colin – I just love how object property keys and array indexes are treated as equal in Javascript. The closest to this coolness that PHP comes is in pseudo-property keys ($obj->$var_key)
never knew this method, very useful.
@Chris – PHP’s ArrayObject class allows you to access properties using array syntax.
@keith – huh…never knew that. Thanks! :D
It’s a good thing to point out that you can almost always avoid eval() by use of myObject[‘key’] reference. for example:
var myObject = {}; $H({ 'a': 1, 'b': 2, 'c': 3 }).each(function(v, k) { myObject[k] = v; });A lot of people think you have to do something like:
var myObject = {}; $H({ 'a': 1, 'b': 2, 'c': 3 }).each(function(v, k) { eval('myObject.' + k + ' = ' + v); });Avoid eval! Eval is evil.
@Timothy: While it is preferable to avoid eval in code that need not be written in that form, as you show, I would like to contest that eval is far from evil.
It’s a basic language construct upon which the entire functional programming paradigm can be built in languages that do not support it natively. Sometimes a problem is better expressed in said paradigm, but the language prevents you from properly exploiting it’s capabilities. This is one of the many ways eval *can* be used for the better of your programming speed, debug-ability and general style of programming.
So please, next time you wish to share your opinion on eval, try to think of the grand picture this language construct fits in, and don’t spread lies about otherwise finely crafted implementations thereof.
Thank you! I was stumped but this got me back on track.
Thank you soooo much, didn’t know this was possible. Spent countless hours trying to refactor my object to make calls easier, wish someone told me about this earlier lol.