How to get in stock product collection by category id in Magento 2.3.3?

Question

I'm using Magento 2.3.3 with multiple websites store that uses different multiple stock sources(multi inventory) and I tried to retrieve product collection by category id like this:

public function __construct(
    \Magento\Catalog\Model\Product\Visibility $catalogProductVisibility,
    \Magento\Catalog\Model\ResourceModel\Product\CollectionFactory $productsCollectionFactory,
    \Magento\Catalog\Model\CategoryFactory $categoryFactory
){
    $this->_catalogProductVisibility  = $catalogProductVisibility;
    $this->_productCollectionFactory  = $productsCollectionFactory;
    $this->_categoryFactory           = $categoryFactory;
}

$collection = $this->_productCollectionFactory->create();
$category = $this->_categoryFactory->create()->load(3);

$_collection->setVisibility($this->_catalogProductVisibility->getVisibleInCatalogIds());
$_collection->addFieldToFilter('status', array('eq' => \Magento\Catalog\Model\Product\Attribute\Source\Status::STATUS_ENABLED));

$_collection = $this->_addProductAttributesAndPrices($_collection)
        ->setCurPage(1);

$_collection->setPageSize($7);

$_collection->addCategoryFilter($category);
$_collection->addAttributeToFilter('is_featured',1);
$_collection->setOrder('created_at','desc');

return $_collection;

The collection will show both in stock and out of stock product collection, how can I filter out the out of stock product and only show the in-stock product collection?

Thanks in advance..!

Answer 1

To get instock product collection. include catalogInventory stock helper class

protected $stockFilter;

public function __construct(
\Magento\Catalog\Model\Product\Visibility $catalogProductVisibility,
\Magento\Catalog\Model\ResourceModel\Product\CollectionFactory $productsCollectionFactory,
\Magento\Catalog\Model\CategoryFactory $categoryFactory,
\Magento\CatalogInventory\Helper\Stock $stockFilter
){
    $this->_catalogProductVisibility  = $catalogProductVisibility;
    $this->_productCollectionFactory  = $productsCollectionFactory;
    $this->_categoryFactory           = $categoryFactory;
    **$this->stockFilter                = $stockFilter;**
}

$collection = $this->_productCollectionFactory->create();
$category = $this->_categoryFactory->create()->load(3);
$_collection->setVisibility($this->_catalogProductVisibility->getVisibleInCatalogIds());

$_collection->addFieldToFilter('status', array('eq' => \Magento\Catalog\Model\Product\Attribute\Source\Status::STATUS_ENABLED));
$_collection = $this->_addProductAttributesAndPrices($_collection)->setCurPage(1);

$this->stockFilter->addInStockFilterToCollection($_collection);// return instock product collection only
$_collection->setPageSize($7);
$_collection->addCategoryFilter($category);
$_collection->addAttributeToFilter('is_featured',1);
$_collection->setOrder('created_at','desc');

return $_collection;

Need to add addInstockFilterToCollection to get only Instock collection. please accept anser if it is helpful. Thanks