folder-listing.js

var path = get('global.workPath')
var files = listFiles(path + '/') // Be sure the path ends with '/'

log(files.length)

/*
 * Helpers
 */

function get(name) { return typeof name === 'number' ? Watch.getJobInfo(name) : Watch.getVariable(name) }
function set(name, value) { typeof name === 'number' ? Watch.setJobInfo(name, value) : Watch.setVariable(name, value) }
function log(msg) { try { Watch.log(toString(msg), 2) } catch(e) { WScript.stdout.WriteLine(toString(msg)) } }
function err(msg) { try { Watch.log(toString(msg), 1) } catch(e) { WScript.stdout.WriteLine(toString(msg)) } }
function exp(string) { return Watch.expandString(string); }
function xml(string) { return Watch.expandString("xmlget('/request[1]/values[1]/" + string + "[1]',Value,KeepCase,No Trim)"); }
function toString(value) { try { return JSON.stringify(value) } catch(e) { return ''+value } }

function listFolders(path) {
  var fs   = new ActiveXObject("Scripting.FileSystemObject")
  var fc   = new Enumerator(fs.GetFolder(path).SubFolders)
  var list = []
  for (; !fc.atEnd(); fc.moveNext()) {
    list.push(fc.item())
  }
  return list
}

function listFiles(path) {
  var fs   = new ActiveXObject("Scripting.FileSystemObject")
  var fc   = new Enumerator(fs.GetFolder(path).files)
  var list = []
  for (; !fc.atEnd(); fc.moveNext()) {
    list.push(fc.item())
  }
  return list
}