Cannot add custom topmenu link with plugin

Question

I want to add custom links to the topmen / a submenu in the topmenu (I need the links for custom filters). To achieve this, I have created a plugin:

app/code/Vendor/Module/etc/frontend/di.xml:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../lib/internal/Magento/Framework/ObjectManager/etc/config.xsd">
    <!-- Plugin to add custom topmenu links -->
    <type name="Magento\Theme\Block\Html\Topmenu">
        <plugin name="Module-topmenu" type="Vendor\Module\Plugin\Block\Topmenu" sortOrder="1"/>
    </type>
</config>

app/code/Vendor/Module/Plugin/Block/Topmenu.php:

namespace Vendor\Module\Plugin\Block;


class Topmenu
{
    /**
     * @var NodeFactory
     */
    protected $nodeFactory;

    public function __construct(
        NodeFactory $nodeFactory
    ) {
        $this->nodeFactory = $nodeFactory;
    }

    public function beforeGetHtml(
        \Magento\Theme\Block\Html\Topmenu $subject,
        $outermostClass = '',
        $childrenWrapClass = '',
        $limit = 0
    ) {

        $node = $this->nodeFactory->create(
            [
                'data' => $this->getNodeAsArray(),
                'idField' => 'unique-id',
                'tree' => $subject->getMenu()->getTree()
            ]
        );

        $subject->getMenu()->addChild($node);
    }

    protected function getNodeAsArray()
    {
        return [
            'name' => 'Testlink',
            'id' => 'testlink',
            'url' => 'http://www.example.com/',
            'has_active' => false,
            'is_active' => false // (expression to determine if menu item is selected or not)
        ];
    }
}

But this does not work, the custom menu link won't appear. Is there an error in my code, or is there another way to add topmenu/submenu links that are not categories?

EDIT: The code seems to be correct. But the site uses a customized theme that did not call the Magento function to render the menu, thus the plugin never ran. Instead, the theme builds the menu "by hand". This issue is nonexistent.

Answer 1

1 – We have to create app/code/Test/TestCustomMenu/etc/di.xml file where we will define our plugin.

<?xml version="1.0"?>
<!--
/**
* @category   Webkul
* @package    Test_TestCustomMenu
* @author     Webkul Software Private Limited
* @license    https://store.webkul.com/license.html
*/
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <!-- Add Plugin for add custom link in navigation -->
    <type name="Magento\Theme\Block\Html\Topmenu">
        <plugin name="add_menu_item_plugin" type="Test\TestCustomMenu\Plugin\Topmenu" sortOrder="10" disabled="false"/>
    </type>
</config>

2 – Now we have to create app/code/Test/TestCustomMenu/Plugin/Topmenu.php . In this file we will modify default getHtml function.This function return list html which is call in navigation menu.We added after plugin of getHtml function for adding our custom link at the end of pre-generated list of html.

<?php
/**
* @category   Webkul
* @package    Test_TestCustomMenu
* @author     Webkul Software Private Limited
* @license    https://store.webkul.com/license.html
*/

namespace Test\TestCustomMenu\Plugin;

class Topmenu
{
    /**
    * @param Context                                   $context
    * @param array                                     $data
    */
    public function __construct(
        \Magento\Customer\Model\Session $session
    ) {
        $this->Session = $session;
    }


    public function afterGetHtml(\Magento\Theme\Block\Html\Topmenu $topmenu, $html)
    {
        $swappartyUrl = $topmenu->getUrl('testCustomMenu/custommenu');//here you can set link
        $magentoCurrentUrl = $topmenu->getUrl('*/*/*', ['_current' => true, '_use_rewrite' => true]);
        if (strpos($magentoCurrentUrl,'testCustomMenu/custommenu') !== false) {
            $html .= "<li class=\"level0 nav-5 active level-top parent ui-menu-item\">";
        } else {
            $html .= "<li class=\"level0 nav-4 level-top parent ui-menu-item\">";
        }
        $html .= "<a href=\"" . $swappartyUrl . "\" class=\"level-top ui-corner-all\"><span class=\"ui-menu-icon ui-icon ui-icon-carat-1-e\"></span><span>" . __("Custom Menu") . "</span></a>";
        $html .= "</li>";
        return $html;
    }
}

After adding above files please run following command :-
php bin/magento setup:di:compile
php bin/magento cache:flush

Now you can check your custom link in navigation menu.

Answer 2

You also need to add Preference: <preference for="Magento\Theme\Block\Html\Topmenu" type="Vendor\Module\Block\Html\Topmenu" />

This is the only way the works for me to overwrite the html!