Method appendColHeader

handsontable/src/tableView.ts:1526–1585

* Append column header to a TH element. * * @private * @param {number} visualColumnIndex Visual column index. * @param {HTMLTableCellElement} TH The table header element. * @param {Function} [label] The function that returns the header label. * @param {number} [headerLevel=0] The i

(
    visualColumnIndex: number,
    TH: HTMLTableCellElement,
    label = this.hot.getColHeader,
    headerLevel = 0
  )

   *                                 values counting from 0 to N).
   */
  appendColHeader(
    visualColumnIndex: number,
    TH: HTMLTableCellElement,
    label = this.hot.getColHeader,
    headerLevel = 0
  ) {
    const getColumnHeaderClassNames = (): string[] => {
      const metaHeaderClassNames =
        visualColumnIndex >= 0 ?
          this.hot.getColumnMeta(visualColumnIndex).headerClassName :
          null;

      if (!metaHeaderClassNames) {
        return [];
      }

      const classes: string[] = Array.isArray(metaHeaderClassNames)
        ? (metaHeaderClassNames as string[])
        : (metaHeaderClassNames as string).split(' ');

      return classes.flatMap(cls => cls.split(' ')).filter(cls => cls.length > 0);
    };

    if (TH.firstChild) {
      const container = TH.firstChild as HTMLElement;

      if (hasClass(container, 'relative')) {
        this.updateCellHeader(
          container.querySelector<HTMLElement>('.colHeader')!, visualColumnIndex, label, headerLevel);

        container.className = '';
        addClass(container, ['relative', ...getColumnHeaderClassNames()]);

      } else {
        empty(TH);
        this.appendColHeader(visualColumnIndex, TH, label, headerLevel);
      }

    } else {
      const { rootDocument } = this.hot;
      const div = rootDocument.createElement('div');
      const span = rootDocument.createElement('span');
      const classNames = getColumnHeaderClassNames();

      div.classList.add('relative', ...classNames);
      span.className = 'colHeader';

      if (this.settings.ariaTags) {
        setAttribute(div, [A11Y_PRESENTATION()]);
        setAttribute(span, [A11Y_PRESENTATION()]);
      }

      this.updateCellHeader(span, visualColumnIndex, label, headerLevel);

      div.appendChild(span);
      TH.appendChild(div);
    }