Magento2: How to convert JSON to Array of nested objects

\Magento\Framework\Json\Helper\Data is deprecated since Magento 100.2.0

You could use \Magento\Framework\Serialize\Serializer\Json instead.

Ie.

 public function __construct(
        \Magento\Framework\Serialize\Serializer\Json $json
    ) {
        $this->json = $json;
    }

 public function yourFunction()
 {
   $jsonDecode = $this->json->unserialize($result);

   $json = $this->json->serialize($jsonDecode);

 }