code: public void refreshColumns() {
          boolean wasEnhanced = enhanced;
          if (enhanced) unEnhance();
          clearHead();
          tBody.clear();
          populateHeadAndBody();
          if (wasEnhanced) enhance();
      }
docs: Refreshes head and body, needed for example after addColumn().
  <br>Currently it's slow and completely re-enhances DataTable, because there is no support
  for dynamic columns in DataTable, see <a href="https://github.com/DataTables/DataTables/issues/273">
  Create columns dynamically</a>