XML parsing syntax for OS X Yosemite JavaScript for Automation?

Has anyone deduced syntax which successfully loads XML from file/string and gives access to the data in OS X Yosemite (10.10) Javascript for Automation ?

Documentation and code samples are still fairly thin (as of Nov 2014), and my inductive skills are running dry on three separate approaches to reading an XML (OPML) file at the moment:

1. Most promising: $.NSXMLDocument

Getting hold of the string data in various ways goes well,

function readTextFromFile(strPath) {
    return $.NSString.stringWithContentsOfFile(strPath);
}
function readDataFromFile(strPath) {
    return $.NSData.alloc.initWithContentsOfFile(strPath);
}
function filePath(strPath) { return Path(strPath); }

But no permutations on this theme have borne fruit:

var strPath='/Users/houthakker/Desktop/notes-2014-11-04.opml',
    dataXML = readData(strPath),
    strXML = readTextFile(strPath),
    oXMLDoc1, oXMLDoc2;

oXMLDoc1 = $.NSXMLDocument.alloc.initWithXMLString(strXML,0,null);
oXMLDoc2 = $.NSXMLDocument.alloc.initWithData(dataXML,0,null);

2. 
   

   Most progress: $.NSXMLParser

   
   

   var oParser = $.NSXMLParser.alloc.initWithData(dataXML); return oParser.parse; //true

   
   

But event-driven parsing seems to require some further complexities which remain opaque to me, and which may not match my simple needs (reading and converting modestly sized OPML files).

3. Most familiar: Application("System Events")

In Applescript this can be done with System Events code:

set fOPML to (POSIX file "/Users/houthakker/Desktop/notes-2014-11-04.opml" as alias) as string
tell application "System Events"
    tell XML file fOPML
    -- now access XML Elements by name or index
end tell

but I haven't found a successful javascript idiom for initializing the XMLFile object with any permutation of a unix Path(), string, or comma-delimited string.

Any thoughts or more successful experience here ?