Issues in using Excel.Application COMObject with Javascript and Spidermonkey (within Sparx EA)

Question

I'm using Sparx Enterprise Architect to create a script that needs to generate an Excel file. Until now I've used VBScript and JScript, but I need for a new project to implement it with Javascript. Sparx EA uses Mozilla SpiderMonkey JS v1.8.

I started with the following code:

function main()
{
    try {
    var objExcel= new COMObject("Excel.Application",true);      
    var objWorkbook = objExcel.Workbooks.Add(true);
    var objWorksheet = objWorkbook.Sheets.Add("",1);
    }   
    catch (ex)
    {
        Session.Output("exception " + ex);
    }   
}
main(); 

Unfortunately this generates the following error: exception TypeError: objWorkbook is undefined

Answer 1

From MS documentation Workbook:

public object Add (object Before, object After, object Count, object Type);

All parameters are optional, if no parameter is passed it returns a Worksheet

You can see online documentation here