Psuedocode for how I'd like zip archivng to work. It gives me full JS to decide if a file belongs or doesn't.

zipExample.js

const zip = require ("davezip");
const fs = require ("fs");
const theArchiveFile = zip.createArchive ('outlines.zip");
                                          
fs.fileloop ("/users/bullmancuso/publicfiles/", function (err, f) { //I made up fs.fileloop, it would be nice ;-)
	if (f.hasExtension (".opml")) {
		zip.addToArchive (f, theArchiveFile);
		}
	});
  
zip.closeArchive (theArchiveFile);

I've gotten the sample code for the archiver package to work locally. So I'm on the road.