Magento 2.3 - Set max compare products to 2

Question

I want to set the limit for the products to compare max 2 product. I tried to create this module: https://magento.stackexchange.com/a/159543/16894

But it seems that this does not work with Magento 2.3.4, because I do not get any errormessage and still can add more than 2 items.

How can I achieve this?

Answer 1

The answer in that topic makes you misunderstand. I've fixed that issue, please do the following steps to limit the number of products in compare products feature:

Step 1: Create registration.php:

File path: app/code/Vendor/Module/registration.php

<?php

use Magento\Framework\Component\ComponentRegistrar;

ComponentRegistrar::register(ComponentRegistrar::MODULE, 'Vendor_Module', __DIR__);

Step 2: Create module.xml:

File path: app/code/Vendor/Module/etc/module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Vendor_Module">
        <sequence>
            <module name="Magento_Catalog"/>
        </sequence>
    </module>
</config>

Step 3: Create the di.xml file:

File path: app/code/Vendor/Module/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Catalog\Controller\Product\Compare\Add">
        <plugin name="LimitCompareProducts" type="Vendor\Module\Plugin\LimitCompareProducts"/>
    </type>
</config>

Step 4: Create LimitCompareProducts.php plugin file:

File path: app/code/Vendor/Module/Plugin/LimitCompareProducts.php

<?php

namespace Vendor\Module\Plugin;

use Magento\Catalog\Controller\Product\Compare\Add;
use Magento\Framework\Controller\Result\RedirectFactory;
use Magento\Framework\Message\ManagerInterface;
use Magento\Catalog\Helper\Product\Compare;

class LimitCompareProducts
{
    const LIMIT_TO_COMPARE_PRODUCTS = 2;

    /**
     * @var ManagerInterface
     */
    protected $messageManager;

    /**
     * @var RedirectFactory
     */
    protected $resultRedirectFactory;

    /** @var Compare */
    protected $helper;

    /**
     * RestrictCustomerEmail constructor.
     * @param Compare $helper
     * @param RedirectFactory $redirectFactory
     * @param ManagerInterface $messageManager
     */
    public function __construct(
        RedirectFactory $redirectFactory,
        Compare $helper,
        ManagerInterface $messageManager
    ) {
        $this->helper = $helper;
        $this->resultRedirectFactory = $redirectFactory;
        $this->messageManager = $messageManager;
    }

    public function aroundExecute(
        Add $subject,
        \Closure $proceed
    ) {

        $count = $this->helper->getItemCount();
        if ($count === self::LIMIT_TO_COMPARE_PRODUCTS) {
            $this->messageManager->addErrorMessage(
                __(
                    'Compare products cannot contain more than %1 item(s)',
                    self::LIMIT_TO_COMPARE_PRODUCTS
                )
            );

            $resultRedirect = $this->resultRedirectFactory->create();
            return $resultRedirect->setRefererOrBaseUrl();
        }

        return $proceed();
    }
}

Step 5: Run the setup:upgrade command to make your new module active, and then compile code, deploy static content:

bin/magento setup:upgrade
bin/magento setup:di:compile
bin/magento setup:static-content:deploy -f

Done. This module compatible with all Magento 2 versions(2.0.x...2.3.x...2.4.x...)