// Gets an array of property names.
PropertyNames()
{
  const columns = new LJCDataColumns();
  let column = columns.Add("Name");
  column = columns.Add("Sequence");

  const names = columns.PropertyNames();
  let result = "";
  for (let index = 0; index < names.length; index++)
  {
    let column = columns.RetrieveAtIndex(index);
    if (LJC.HasText(result))
    {
      result += ", ";
    }
    result += column.PropertyName;
  }

  // result:
  // Name, Sequence
}