AR: Rename file with counter, per folder (Pre-Batch script)

const ZERO_PAD = 3;
const FILE_PREFIX = "Archivo ";
var temp_path = app.getItem(0).path;
var file_counter=0;

// Function that add leading zeros to any string
function zpad(str, nb_digits) {
    if (str.length < nb_digits) { return (Array(nb_digits - str.length + 1).join('0') + str); }
    else { return str; }
}