How to use the domutils.compareDocumentPosition function in domutils

var current = pending.shift();
    while (current) {
      if (memory.indexOf(current) < 0) {
        memory.push(current);
        if (current.children && !isItem(current)) {
          pending = pending.concat(current.children);
        }
        var props = getPropertyNames(current);
        if (props.length > 0) {
          results.push(current);
        }
      }
      current = pending.shift();
    }

    results.sort(DOM.compareDocumentPosition);

    return results;
  }