<?php
namespace VendorAddallControllerIndex;
use MagentoFrameworkAppActionContext;
class Add extends MagentoFrameworkAppActionAction{
    protected $resultJsonFactory;
    protected $request;
    protected $form_key;
    protected $cart;
    protected $product;
    protected $message_manager;
    public function __construct(Context$context,MagentoFrameworkControllerResultJsonFactory $resultJsonFactory,MagentoFrameworkAppRequestInterface $request,MagentoFrameworkDataFormFormKey $form_key,MagentoCheckoutModelCart $cart,MagentoCatalogModelProduct $product,MagentoFrameworkMessageManagerInterface $message_manager) {
        $this->request=$request;
        $this->resultJsonFactory=$resultJsonFactory;
        $this->form_key = $form_key;
        $this->cart = $cart;
        $this->product = $product;
        $this->message_manager = $message_manager;
        parent::__construct($context);
    }
    public function execute() {
        $result = $this->resultJsonFactory->create();
        $childs_product_arr=json_decode($this->request->getParam('childs_product_arr'));
        $parent_product=json_decode($this->request->getParam('parent_product_id'));
        $parent_product=$parent_product[0];
        try {
                $params = [];
                foreach ($childs_product_arr as $child_product){
                    $options = [];
                    $_product = $this->product->load($parent_product);
                    $child_product=(array)$child_product;
                    $param = array(
                        'form_key' => $this->form_key->getFormKey(),
                        'super_attribute' => $options,
                        'qty' => 1,
                        'selected_configurable_option' => $child_product['simple_product_id'],
                    );
                    $this->cart->addProduct($_product->getId(), $param);

                }
                $this->cart->save();
                $msg="You added {$_product->getName()} to your shopping cart";
                $this->message_manager->addSuccess(__($msg));
                return $result->setData(['success' => true]);
        } catch (Exception $e) {
            $this->message_manager->addSuccess(__($e->getMessage()));
            return $result->setData(['success' => false,'error'=>$e->getMessage()]);
        }
    }
}