Get the most out of the JavaScript arguments object

So if you're a CF'er who has doubled down on AJAX then you really should take a minute to get to know the JavaScript arguments object.

In a nutshell, any function object in JavaScript 1.4 or beyond contains a super awesome arguments object. Why is this important? Well it matters if your function needs to make decisions based on the existence of expected arguments, set the value of an argument, count the number of passed arguments and a whole lot of other scenarios.

So for starters, please keep in mind that although the arguments object might look like an array, it is not an array. If you need it to be a true array then it can be converted into one in short order doing something like this...

Another obvious but important point to remember is that the arguments object can only be referenced inside of the function's body. If you try to manipulate it outside of the body of the function a massive energy displacement will occur like when Desmond failed to press "the button" on LOST. Unlike Desmond you cannot survive a large scale electromagnetic event so do not try to access the arguments object outside of the function's body (you have been warned).

Contrary to what some folks might tell it is also possible (and sometimes very useful) to call a function with a greater number of arguments then your function was originally designed to accept. To analyze exactly what your function received at the time it was called you can use the object's length property.

Finally, we've got the arguments.callee property. Yes, like Whitney Houston I've went and saved the best for last. Why? Well because you can use arguments.callee in an anonymous recursive function like so...

Please note that I plagiarized the last snippet of code from mozilla.org because I'm lazy.

Anyway, there you have it - a few good reasons to make friends with the JavaScript arguments object.