hashByHref example

/** * {@inheritdoc} */
  public function normalize($object, $format = NULL, array $context = []): array|string|int|float|bool|\ArrayObject|NULL {
    assert($object instanceof LinkCollection);
    $normalized = [];
    /** @var \Drupal\jsonapi\JsonApiResource\Link $link */
    foreach ($object as $key => $links) {
      $is_multiple = count($links) > 1;
      foreach ($links as $link) {
        $link_key = $is_multiple ? sprintf('%s--%s', $key, $this->hashByHref($link)) : $key;
        $attributes = $link->getTargetAttributes();
        $normalization = array_merge(['href' => $link->getHref()], !empty($attributes) ? ['meta' => $attributes] : []);
        // Checking access on links is not about access to the link itself;         // it is about whether the current user has access to the route that is         // *targeted* by the link. This is done on a "best effort" basis. That         // is, some links target routes that depend on a request to determine if         // they're accessible or not. Some other links might target routes to         // which the current user will clearly not have access, in that case         // this code proactively removes those links from the response.         $access = $link->getUri()->access($this->currentUser, TRUE);
        $cacheability = CacheableMetadata::createFromObject($link)->addCacheableDependency($access);