Check user logged in or not?

Question

I want to check that user is logged in or not in order to hide add to cart button for guest users. I have created a module in which I have override addtocart.phtml file and added the below code:

<?php

$test = \Magento\Framework\App\ObjectManager::getInstance();
$context = $test->get('Magento\Framework\App\Http\Context');
$isLoggedInn = $context->getValue(\Magento\Customer\Model\Context::CONTEXT_AUTH); 
?>

<?php if( $isLoggedInn ) : ?>

<?php echo "text"; ?>

<?php endif; ?>

It's working but is it a right approach because I have use object manager directly in phtml file.