Trouble with cart add module

Question

Trying to create a module that redirects the customer to the account creation page when they add to cart if they are not logged in, I have the following code in app/code/Mason/CheckoutRedirect/Plugin/Checkout/Controller/Cart/Add.php:

namespace Mason\CheckoutRedirect\Plugin\Checkout\Controller\Cart;

class Add
{
    /**
     * @var \Magento\Framework\ObjectManagerInterface
     */
    protected $objectManager;

    /**
     * @var \Magento\Framework\Controller\Result\RedirectFactory
     */
    protected $resultRedirectFactory;

    /**
     * @var \Magento\Framework\UrlInterface
     */
    protected $url;

    /**
     * Data constructor.
     *
     * @param \Magento\Framework\ObjectManagerInterface $objectManager
     * @param \Magento\Framework\Controller\Result\RedirectFactory $resultRedirectFactory
     * @param \Magento\Framework\UrlInterface $url
     */
    public function __construct(
        \Magento\Framework\ObjectManagerInterface $objectManager,
        \Magento\Framework\Controller\Result\RedirectFactory $resultRedirectFactory,
        \Magento\Framework\UrlInterface $url
    ) {
        $this->objectManager = $objectManager;
        $this->resultRedirectFactory = $resultRedirectFactory;
        $this->url = $url;
    }

    public function aroundExecute(
        \Magento\Checkout\Controller\Cart\Add $subject,
        \Closure $proceed
    ) {
        $contactUrl = $this->url->getUrl('customer/account/create');
        $result = [];
        $result['backUrl'] = $contactUrl;

        $subject->getResponse()->representJson(
            $this->objectManager->get('Magento\Framework\Json\Helper\Data')->jsonEncode($result)
        );
        return;
    }
}

All this is doing is returning a JSON object:

{"backUrl":"https://domain.com/customer/account/create/"}

But it isn't redirecting

Answer 1

Yes, it's getting the plugin correctly, but it only returns the JSON object, rather than doing the redirect that I want it to do