magento2/app/code/Magento/NewsletterGraphQl/Model/Resolver/IsSubscribed.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
declare(strict_types=1);

namespace Magento\NewsletterGraphQl\Model\Resolver;

use Magento\Customer\Api\Data\CustomerInterface;
use Magento\Framework\App\ObjectManager;
use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\GraphQl\Config\Element\Field;
use Magento\Framework\GraphQl\Query\ResolverInterface;
use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
use Magento\Newsletter\Model\SubscriberFactory;
use Psr\Log\LoggerInterface;

/**
 * Customer is_subscribed field resolver
 */
class IsSubscribed implements ResolverInterface
{
    /**
     * @var SubscriberFactory
     */
    private SubscriberFactory $subscriberFactory;

    /**
     * @var LoggerInterface
     */
    private LoggerInterface $logger;

    /**
     * @param SubscriberFactory $subscriberFactory
     * @param LoggerInterface|null $logger
     */
    public function __construct(
        SubscriberFactory $subscriberFactory,
        LoggerInterface $logger = null
    ) {
        $this->subscriberFactory = $subscriberFactory;
        $this->logger = $logger ?? ObjectManager::getInstance()->get(LoggerInterface::class);
    }

    /**
     * @inheritdoc
     */
    public function resolve(
        Field $field,
        $context,
        ResolveInfo $info,
        array $value = null,
        array $args = null
    ) {
        if (!isset($value['model'])) {
            throw new LocalizedException(__('"model" value should be specified'));
        }
        $customerId = (int)$value['model']->getId();

        $extensionAttributes = $context->getExtensionAttributes();
        if (!$extensionAttributes) {
            return false;
        }

        $store = $extensionAttributes->getStore();
        if (!$store) {
            $this->logger->error(__('Store not found'));

            return false;
        }

        return $this->isSubscribed($customerId, (int)$store->getWebsiteId());
    }

    /**
     * Get customer subscription status
     *
     * @param int $customerId
     * @param int $websiteId
     * @return bool
     */
    public function isSubscribed(int $customerId, int $websiteId): bool
    {
        $subscriberFactory = $this->subscriberFactory->create();
        $subscriptionData = $subscriberFactory->loadByCustomer($customerId, $websiteId);

        return $subscriptionData->isSubscribed() ?? false;
    }
}