Magento 2: How to override Block file Configurable.php?

Question

In magento 2, using Preference Configurable.php file is not simply override, Is this is magento 2 bug?

I have override simply using preference method inside di.xml file but its not override.

I want to override function getJsonConfig() from file. Using only Simply override method of magento 2. Code for di.xml file

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\ConfigurableProduct\Block\Product\View\Type\Configurable" type="Package\Configurable\Block\Product\View\Type\Configurable"/>    
</config>

Is there any trick or method to override Configurable.php file?

Thanks.

Answer 1

VendorName/ModuleName/etc/frontend/di.xml

<?xml version="1.0"?>

    <type name="Magento\ConfigurableProduct\Block\Product\View\Type\Configurable">
        <plugin name="vendor_configurable_product_configurable" type="VendorName\ModuleName\Block\ConfigurableProduct\Product\View\Type\Configurable" sortOrder="1"/>
    </type>
</config>

namespace VendorName\Module\Block\ConfigurableProduct\Product\View\Type;

use Magento\Framework\Json\EncoderInterface;
use Magento\Framework\Json\DecoderInterface;
class Configurable
{

    protected $jsonEncoder;
    protected $jsonDecoder;

    public function __construct(
        EncoderInterface $jsonEncoder,
        DecoderInterface $jsonDecoder
    ) {

        $this->jsonDecoder = $jsonDecoder;
        $this->jsonEncoder = $jsonEncoder;
    }

    public function aroundGetJsonConfig(
        \Magento\ConfigurableProduct\Block\Product\View\Type\Configurable $subject,
        \Closure $proceed
    )
    {
        $config = $proceed();
        $config = $this->jsonDecoder->decode($config);
        $config['url'] = 'sample_url';
        return $this->jsonEncoder->encode($config);
    }
}

You can use after plugin following way:

namespace VendorName\Module\Block\ConfigurableProduct\Product\View\Type;

use Magento\Framework\Json\EncoderInterface;
use Magento\Framework\Json\DecoderInterface;
class Configurable
{

    protected $jsonEncoder;
    protected $jsonDecoder;

    public function __construct(
        EncoderInterface $jsonEncoder,
        DecoderInterface $jsonDecoder
    ) {

        $this->jsonDecoder = $jsonDecoder;
        $this->jsonEncoder = $jsonEncoder;
    }

    public function afterGetJsonConfig(
        \Magento\ConfigurableProduct\Block\Product\View\Type\Configurable $subject,
        $config
    )
    {
        $config = $this->jsonDecoder->decode($config);
        $config['url'] = 'sample_url';
        return $this->jsonEncoder->encode($config);
    }
}