Override a field in a taxonomy terms view

I have a taxonomy terms view, filtered by a vocabulary. I would like to add the dashes before the term name like in the Parent terms field on the edit term page. The code in TermForm.php does that when creating $options using str_repeat based on the item's depth.

This is the code from TermForm.php:

$tree = $taxonomy_storage->loadTree($vocabulary->id());
$options = ['<' . $this->t('root') . '>'];
if (empty($parent)) {
  $parent = [0];
}

foreach ($tree as $item) {
  if (!in_array($item->tid, $exclude)) {
    $options[$item->tid] = str_repeat('-', $item->depth) . $item->name;
  }
 }
}

I copied core/modules/views/templates/views-view-field.html.twig to my module's templates directory and renamed it views-view-field--my-view-name--name.html.twig I added hook_theme to the module file to start using the template.

/**
 * Implements hook_theme().
 */
function my_module_theme($existing, $type, $theme, $path) {
  return [
    'views_view_field__my_view_name__name'=> [
      'render element' => 'elements',
      'template' => 'views-view-field--my-view-name--name',
    ],
  ];
}

If I add some markup to the template, like <h3>hello</h3>, hello is printed on the View's page but, no data is being passed to the template.

Ultimately I need to get the term object and update it with

str_repeat('-', $item->depth) . $item->name

before passing the field to the template. I'm guessing I get the term object in a preprocessor and add the updated name field to hook_theme?

It turns out I don't need the template. Using hook_preprocess_views_view_field() with the following code was all that was required:

/**
 * Implements hook_preprocess_views_view_field().
 */
function my_module_preprocess_views_view_field(&$variables) {
  $view = $variables['view'];
  $field = $variables['field'];
  $field_id = $field->field;
  if (
    $view->storage->id() === 'my_view_name' &&
    $view->current_display === 'my_display' &&
    $field_id === 'name'
  ) {
    $tid = $variables['row']->_entity->id();
    $label = $variables['row']->_entity->label();

    $parents = \Drupal::entityTypeManager()
      ->getStorage('taxonomy_term')
      ->loadAllParents($tid);
    $depth = count($parents);
    $path = \Drupal::service('path_alias.manager')
      ->getAliasByPath('/taxonomy/term/' . $tid);

    $link = '<a href="' . $path . '">' . $label . '</a>';
    $variables['output'] = Markup::create(str_repeat('-', $depth) . $link);
  }
}

solved the problem.

I think this line

    $link = '<a href="' . $path . '">' . $label . '</a>';

can be improved, but it will do for now.