Method getGroups

/**
 * Method to get the field option groups.
 *
 * @return  array  The field option objects as a nested array in groups.
 *
 * @since   1.7.0
 * @throws  \UnexpectedValueException
 */
protected function getGroups()
{
    $groups = array();
    $label = 0;
    foreach ($this->element->children() as $element) {
        switch ($element->getName()) {
            // The element is an <option />
            case 'option':
                // Initialize the group if necessary.
                if (!isset($groups[$label])) {
                    $groups[$label] = array();
                }
                $disabled = (string) $element['disabled'];
                $disabled = $disabled === 'true' || $disabled === 'disabled' || $disabled === '1';
                // Create a new option object based on the <option /> element.
                $tmp = HTMLHelper::_('select.option', $element['value'] ? (string) $element['value'] : trim((string) $element), Text::alt(trim((string) $element), preg_replace('/[^a-zA-Z0-9_\\-]/', '_', $this->fieldname)), 'value', 'text', $disabled);
                // Set some option attributes.
                $tmp->class = (string) $element['class'];
                // Set some JavaScript option attributes.
                $tmp->onclick = (string) $element['onclick'];
                // Add the option.
                $groups[$label][] = $tmp;
                break;
            // The element is a <group />
            case 'group':
                // Get the group label.
                if ($groupLabel = (string) $element['label']) {
                    $label = Text::_($groupLabel);
                }
                // Initialize the group if necessary.
                if (!isset($groups[$label])) {
                    $groups[$label] = array();
                }
                // Iterate through the children and build an array of options.
                foreach ($element->children() as $option) {
                    // Only add <option /> elements.
                    if ($option->getName() !== 'option') {
                        continue;
                    }
                    $disabled = (string) $option['disabled'];
                    $disabled = $disabled === 'true' || $disabled === 'disabled' || $disabled === '1';
                    // Create a new option object based on the <option /> element.
                    $tmp = HTMLHelper::_('select.option', $option['value'] ? (string) $option['value'] : Text::_(trim((string) $option)), Text::_(trim((string) $option)), 'value', 'text', $disabled);
                    // Set some option attributes.
                    $tmp->class = (string) $option['class'];
                    // Set some JavaScript option attributes.
                    $tmp->onclick = (string) $option['onclick'];
                    // Add the option.
                    $groups[$label][] = $tmp;
                }
                if ($groupLabel) {
                    $label = \count($groups);
                }
                break;
            // Unknown element type.
            default:
                throw new \UnexpectedValueException(sprintf('Unsupported element %s in GroupedlistField', $element->getName()), 500);
        }
    }
    reset($groups);
    return $groups;
}