exclude_bundles.module

<?php

use Drupal\Core\Database\Query\AlterableInterface;

/**
 * Implements hook_query_TAG_alter
 */
function exclude_bundles_query_search_node_search_alter(AlterableInterface $query) {
  // ideas taken from:
  //   https://www.phase2technology.com/blog/restricting-search-results-in-drupal-7/
  // see the config file exclude_bundles.settings.yml
  $config = \Drupal::config('exclude_bundles.settings');
  $bundles_config = $config->get('bundles');
  $hidden_bundles = [];
  if (!empty($bundles_config)) {
    foreach ($bundles_config as $k => $v) {
      // if the value is not 0, add it to the array
      if ($v) {
        $hidden_bundles[] = $k;
      }
    }
  }

  if (!empty($hidden_bundles)) {
    // add the extra table to join based on config logic
    $query->join('node', 'n2', 'n.nid = n2.nid');
    $query->condition('n2.type', $hidden_bundles, 'NOT IN');
  }
}


function exclude_bundles_form_search_form_alter(&$form, &$form_state, $form_id) {
  $config = \Drupal::config('exclude_bundles.settings');
  $bundles_config = $config->get('bundles');
  $hidden_bundles = [];
  if (!empty($bundles_config)) {
    foreach ($bundles_config as $k => $v) {
      // if the value is not 0, add it to the array
      if ($v) {
        $hidden_bundles[$k] = $k;
      }
    }
  }

  // get the original array of all types from the form
  $array_of_all_bundles = $form['advanced']['types-fieldset']['type']['#options'];

  // remove the hidden bundles from the list of all content types
  $array_of_non_excluded_bundles = array_diff_key($array_of_all_bundles, $hidden_bundles);

  $form['advanced']['types-fieldset']['type'] = array(
    '#type' => 'checkboxes',
    '#options' => $array_of_non_excluded_bundles
  );

}