botframework-webchat-component/src/Utils/tabbableElements.ts

React component of botframework-webchat

export default function tabbableElements(element?: HTMLElement): HTMLElement[] {
  // This is an incomplete list, due to the complexity of testing for every scenario.
  // For full-list, please refer to https://allyjs.io/data-tables/focusable.html
  const candidates: ArrayLike<HTMLElement> =
    element?.querySelectorAll(
      'a[href], area[href], audio[controls], button:not(:disabled), iframe, input:not(:disabled), keygen, select:not(:disabled), summary, textarea:not(:disabled), video[controls], [contenteditable], [tabindex]'
    ) || [];

  return ([] as HTMLElement[]).filter.call(candidates, (element: HTMLElement) => {
    const tabIndexAttribute = element.attributes.getNamedItem('tabindex');

    if (tabIndexAttribute && tabIndexAttribute.specified) {
      const value = parseInt(tabIndexAttribute.value, 10);

      return value >= 0 || (isNaN(value) && element.nodeName.toLowerCase() === 'input');
    }

    return true;
  });
}