code: function findTabbable (el, shouldSearchRootNode) {
    return findFocusable(el, (element) => {
      return !isInvalidTabIndex(element.getAttribute('tabindex'))
    }, shouldSearchRootNode)
  }
docs: ---
  category: utilities/a11y
  ---
  
  Given an element, finds and returns all visible, tabbable children.
  Tabbable elements include input, select, textarea, button, and object.
  Anchor tags are also tabbable if they include an href or zero or positive
  tabindex attribute (to include elements with negative tabindex attributes,
  use findFocusable).
  
  @param {ReactComponent|DomNode} el - component or DOM node
  @param {Boolean} shouldSearchRootNode - should the root node be included in the search
  @returns {Array} array of all tabbable children