Product Sort By Price: Low to High and High to Low Magento 2.3

Today’s tutorial we are showing, how to add a new filter option in the product listing area of Magento 2.3. Here we are adding price sorting options such as Low to High and  High to Low.

We are not discussing how to create a Magento 2 module here, as we assume you have already a module ready.

Basically we use two different techniques here 1) preference method and 2) plugin method to do necessary overriding of the functionality.

Step #1

Create your di.xml in app/code/[Vendor]/[Module]/etc/frontend/di.xml

<?xml version="1.0"?>
    <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../lib/internal/Magento/Framework/ObjectManager/etc/config.xsd">
    
    <preference for="Magento\Catalog\Block\Product\ProductList\Toolbar" type="[Vendor]\[Module]\Plugin\Catalog\Block\Toolbar" />

    <type name="Magento\Catalog\Model\Config">
        <plugin name="estore_custom_catalog_model_config" type="[Vendor]\[Module]\Plugin\Catalog\Model\Config"/>
    </type>

    </config>

We are overriding two methods from two files, those responsible for this functionality.

• afterToOptionArray() from Magento\Catalog\Model\Config
• setCollection() from Magento\Catalog\Block\Product\ProductList\Toolbar

Step #2

Create  a file called Config.php in the folder  app/code/[Vendor]\[Module]\Plugin\Catalog\Model\Config and add the below code.

<?php

namespace [Vendor]\[Module]\Plugin\Catalog\Model;

class Config
{
    public function afterGetAttributeUsedForSortByArray(
        \Magento\Catalog\Model\Config $catalogConfig,
        $options
    ) {

        unset($options['price']);
        $options['low_to_high'] = 'Price - Low To High';
        $options['high_to_low'] = 'Price - High To Low';
        return $options;

    }

}

In this step we have wrote a after plugin to inject the desired options to toolbar sort. We have unset the already existing price as our new options using for the same purpose.

Step #3

Create a file called Toolbar.php in app/code/[Vendor]/[Module]/Plugin/Catalog/Block and add the below content to it.

<?php
namespace [Vendor]\[Mdouel]\Plugin\Catalog\Block;

class Toolbar extends \Magento\Catalog\Block\Product\ProductList\Toolbar
{

    /**
     * Set collection to pager
     *
     * @param \Magento\Framework\Data\Collection $collection
     * @return \Magento\Catalog\Block\Product\ProductList\Toolbar
     */
    public function setCollection($collection)
    {
        $this->_collection = $collection;

        $this->_collection->setCurPage($this->getCurrentPage());

        // we need to set pagination only if passed value integer and more that 0
        $limit = (int)$this->getLimit();
        if ($limit) {
            $this->_collection->setPageSize($limit);
        }
        if ($this->getCurrentOrder()) {
            if (($this->getCurrentOrder()) == 'position') {
                $this->_collection->addAttributeToSort(
                    $this->getCurrentOrder(),
                    $this->getCurrentDirection()
                );
            } else {
                if ($this->getCurrentOrder() == 'high_to_low') {
                    $this->_collection->setOrder('price', 'desc');
                } elseif ($this->getCurrentOrder() == 'low_to_high') {
                    $this->_collection->setOrder('price', 'asc');
                }

            }
        }
        return $this;
    }

}

This is a preference method that use to override a function in Magento 2.

Step #4

Run the following commands

php bin/magento setup:di:compile
php bin/magento cache:flush

Hope this solved your problem.