<?php
/**
* Implements hook_token_info().
*/
function mycustomtokenmodule_token_info() {
   $type = [
       'name' => t('Custom Token'),
       'description' => t('Tokens for custom things.'),
   ];
   $node['title'] = [
       'name' => t("Node Title"),
       'description' => t('The node\'s title'),
   ];
   $node['dateformat'] = [
       'name' => t("Custom Date Format"),
       'dynamic' => TRUE,
       'description' => t('Show a custom format for the current date'),
   ];
   return [
       'types' => ['customtoken' => $type],
       'tokens' => ['customtoken' => $node],
   ];
}
/**
* Implements hook_tokens().
*/
function mycustomtokenmodule_tokens($type, $tokens, array $data, array $options, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata) {
   $replacements = [];
   
   if ($type == 'customtoken' && !empty($data['node'])) {
       foreach ($tokens as $name => $original) {
           switch ($name) {
               case 'title':
                   $replacements[$original] = $data['node']->getTitle();
               break;
           }
       }
       if ($dateTokens = \Drupal::token()->findWithPrefix($tokens, 'dateformat')) {
           // var_dump($dateTokens)
           // retult: array(1) { ["Y-m-d"]=> string(30) "[customtoken:dateformat:Y-m-d]" }
           foreach ($dateTokens as $format => $original) {
               $replacements[$original] = date($format);
           }
       }
   }
   return $replacements;
}