Looking for a way to export Object/Shape or Artboard size data to a CSV or similar File

Hey brother. No apologies necessary. Everybody's gotta learn at some point, and I learned what I know from the brilliant folks around here who helped me along in my journey.

The code you have there appears to work just fine for building the appropriate 2D array for the csv data. great job. So it looks like your sticking point was getting that data into an output file. You can delete that whole pseudo-code section and replace it with this:

var outFile = File("~/Desktop/super_awesome_csv_data.csv");
outFile.open("w");
outFile.write(rows.join("\n"));
outFile.close();

That's all you need to write your data to a local file (or you could just as easily write to a network volume or mounted external drive, etc.  You can use relative file paths as well if you prefer, but I've had better long term results with absolute paths.

Notice the second to last line that uses the .write() method. I'm passing in the result of rows.join("\n"); The join method does essentially what your getCSVtext() function does. It takes the array "rows" and returns a new string by concatenating all of the elements and separating them by the given character, eg "\n". Since we have a 2D array, that means that this join() function will return several arrays, separated by a new line character. So that's almost what we want, right...? But what about a comma separated string of those values??? Default javascript behavior to the rescue! When you print an array (or use the .join() method) there's an implicit call to the Array.toString() function for which the default output is a string with comma separated values from the array. For example: 

var fruits = ["banana","apple","orange"];
$.writeln(fruits); // output: "banana, apple, orange"

So that's perfect. Because when we join the elements of the rows array, it automatically converts each subarray to a comma separated string which is exactly what we want for our csv data. You can use this same logic in your alert as well. 

Anywho, that's how you can get your own code working. However, there are a few other issues going on in your code that should be addressed. You have some global variable definitions which should be avoided at all costs. An example of this is where you define the variable "layer". if you don't explicitly use "var" when declaring the variable, and that variable doesn't already exist in the appropriate scope, then the variable will be created in the global scope where it can cause issues.

The second issue is that you've overwritten the default "document" variable. When you create a variable for the active document, use "doc" or "docRef" instead so you don't interfere with preexisting default variables.

And third, apropos of the aforementioned scope issues, it's always a good idea to wrap your entire script in some kind of container function. This helps ensure that all of the variables you create will remain within the scope of your current script and won't effect the performance or behavior of any other script. 

Lastly, and this isn't a critique as much as it is simply advice. There's an old addage in programming.. DRY. Don't repeat yourself. The beauty of coding is that you can write something once and then use it a million times if you want. So any time you find yourself writing the same thing more than a couple of times, it's probably a candidate for abstraction.

An example of this is converting points to inches. The process of converting points to inches never changes, so it's a perfect candidate for a function. Likewise, rounding to the nearest 8th inch. The logic never changes. so it's easier to write code if you can call a simple function and pass the number in. Then your code won't be cluttered with repetitious code like 

var itemWtoIn   = item.width * .01389;    
// Convert W from Points > Inches

    var itemWrnd    = (Math.ceil((itemWtoIn.toFixed(3)) * 😎 / 8);      
// Round W up to nearest 1/8" for Arch. Measurement

    var itemHtoIn   = item.height * .01389;  
// Convert W from Points > Inches

    var itemHrnd    = (Math.ceil((itemHtoIn.toFixed(3)) * 😎 / 8);      
// Round H up to nearest 1/8" for Arch. Measurement

But instead, it could look like this:

function ptToInch(pt)
{
    //convert points to inches
    return pt * .01389;
}

function roundTo8th(num)
{
    //round the given number to the nearest 1/8"
    return Math.ceil((num.toFixed(3)) * 😎 / 8;
}

function getItemWidthHeight(item)
{
    var width = roundTo8th(ptToInch(item.width));
    var height = roundTo8th(ptToInch(item.height));
    return [item.name, width, height];
}

I've taken the liberty of rewriting the whole script utilizing the above advice. I've modularized everything so that it's easily reusable and easier to read and update. You can find it here:

https://github.com/wdjsdev/public_illustrator_scripts/blob/master/export_doc_data.js

Let me know if this was helpful or if it was a rambling wall of nonsense. Happy to answer any follow up questions.