How to get all children product from parent configurable product in magento2

Question

I need to display some custom attribute from children product in checkout, I study for long time to come out a stupid solution

1. Override Magento\Swatches\Block\Product\Renderer\Configurable
2. Inject productRepository

3. Get children product directly from productRepository

   $currentProduct = $this->getProduct();
   $childrenIds = $currentProduct->getTypeInstance()->getChildrenIds($currentProduct->getId());
   
   $childrenProducts = [];
   foreach ($childrenIds[0] as $childrenId) {
       $childrenProduct = $this->productRepository->getById($childrenId);
       $childrenProducts[] = $childrenProduct->getData()['customexxxx'];
   
   }
   

Anyone know a smart way to do it ?

Answer 1

You have to just keep below code inside block file and call function inside your template,

protected $productFactory;
protected $dataObjectHelper;
protected $productRepository;

public function __construct(        
    \Magento\Framework\View\Element\Template\Context $context,                   
    \Magento\Catalog\Api\Data\ProductInterfaceFactory $productFactory,  
    \Magento\Catalog\Api\ProductRepositoryInterface $productRepository,    
    \Magento\Framework\Api\DataObjectHelper $dataObjectHelper,
    array $data = [] 
){      
    $this->productFactory = $productFactory;      
    $this->productRepository = $productRepository;        
    $this->dataObjectHelper = $dataObjectHelper;
    parent::__construct($context,$data);    
}


     public function getConfigChildProductIds($id){
            $product = array();
            if(is_numeric($id)){           
                $product = $this->productRepository->getById($id); 
            }else{
                return;
            } 

            if(!isset($product)){
                return;
            }

            if ($product->getTypeId() != \Magento\ConfigurableProduct\Model\Product\Type\Configurable::TYPE_CODE) {
                return [];
            }

            $storeId = $this->_storeManager->getStore()->getId();

            $productTypeInstance = $product->getTypeInstance();
            $productTypeInstance->setStoreFilter($storeId, $product);
            $usedProducts = $productTypeInstance->getUsedProducts($product);
            $childrenList = [];       

            foreach ($usedProducts  as $child) {
                $attributes = [];
                $isSaleable = $child->isSaleable();

                //getting in-stock product
                if($isSaleable){
                    foreach ($child->getAttributes() as $attribute) {
                        $attrCode = $attribute->getAttributeCode();
                        $value = $child->getDataUsingMethod($attrCode) ?: $child->getData($attrCode);
                        if (null !== $value && $attrCode != 'entity_id') {
                            $attributes[$attrCode] = $value;
                        }
                    }

                    $attributes['store_id'] = $child->getStoreId();
                    $attributes['id'] = $child->getId();
                    /** @var \Magento\Catalog\Api\Data\ProductInterface $productDataObject */
                    $productDataObject = $this->productFactory->create();
                    $this->dataObjectHelper->populateWithArray(
                        $productDataObject,
                        $attributes,
                        '\Magento\Catalog\Api\Data\ProductInterface'
                    );
                    $childrenList[] = $productDataObject;
                }
            }

            $childData = array();
            foreach($childrenList as $child){
                $childData[] = $child;
            }

            return $childData;
        }

Inside template file call ,

 $productId = 10 //parent product id..
 $childObj = $block->getConfigChildProductIds($productId);
    foreach ($childObj as $child){                 
       $getChildId[] = $child->getData();
    }
    echo "<pre>";print_r($getChildId);

Answer 2

Note that the answer to this question isn't necessarily the correct one. Although the output seems to work, it's not really the Magento 2-way on doing this. First of, use service contracts to get the child products of a configurable. A good example can be found in my answer to this question: https://magento.stackexchange.com/a/155252/2030

Secondly, since you're now set with data models, not inheritance-based models, you need to use the getCustomAttribute()-method to get non-default product attributes. For example:

$attribute = $productModel->getCustomAttribute('foo');
echo $attribute->getValue();