Within bootstrap theme, print radio item with label and input as siblings instead of parent -> child

Question

By default, Bootstrap will render the input radio and checkbox elements as children of the label. This is done in Drupal\bootstrap\Plugin\Preprocess\FormElement, starting at line 45:

// Place single checkboxes and radios in the label field.
if (($checkbox || $radio)) {
  $label = Element::create($variables['label']);
  $children = &$label->getProperty('children', '');

In some instances, I don't want these printed as siblings - how can I undo this? form-element.html.twig isn't helpful unless I can somehow print the children first e.g. {{ label.#children }} and then twig will know not to print them again. Not sure if that solution is even possible.

Thanks!

Answer 1

At first I was going to say hook_form_alter, but when I started digging into the Bootstrap theme I found they've created their own plugin system. I would checkout this page, you might be able to get to the render array by creating a Bootstrap theme plugin: https://drupal-bootstrap.org/api/bootstrap/docs%21plugins%21Form.md/group/plugins_form/8

Answer 2

As @icicleking states, bootstrap uses theme plugins that can be extended. So that we have a thorough answer for what I did I'll post it separately here.

Extend \Drupal\bootstrap\Plugin\Preprocess\FormElement. There's only one method, preprocessElement. In my case I replaced the following:

// Place single checkboxes and radios in the label field.
if (($checkbox || $radio)) {
  $label = Element::create($variables['label']);

with

// Place single checkboxes and radios in the label field.
if (($checkbox || $radio) && !$element->hasProperty('no_wrap_label')) {
  $label = Element::create($variables['label']);

Then you can use the no_wrap_label property on any element that you don't want to be wrapped inside a label, I'm using hook_preprocess_form_element:

function your_module_preprocess_form_element(&$variables) {
  if ($variables['name'] == 'field_field_name') {
    $variables['element']['#no_wrap_label'] = TRUE;
  }
}