Magento 2: get order id on success page

Question

I'm trying to put the conversion event snippet into my success page, but I dont know how do I get the order_id to pass with.

My code is:

gtag('event', 'conversion', {
        'send_to': '...',
        'transaction_id': '<?= $orderId ?>'
    });

But how do I define the $orderId on success page's head tag?

Answer 1

If you have custom block then, just inject this below code in your block file :

Construct Method

protected $checkoutSessionFactory;

public function __construct(
    \Magento\Checkout\Model\SessionFactory $checkoutSessionFactory 
){
    $this->checkoutSessionFactory = $checkoutSessionFactory;
}

public function checkoutSessionObj()
{
    return $this->checkoutSessionFactory->create();
}

After that, you can use this below code in your phtml file.

$orderObj = $block->checkoutSessionObj()->getLastRealOrder();
echo $orderObj->getEntityId(); //Entity Id
echo $orderObj->getIncrementId(); //Increment Id

Object Manager Method :

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$orderObj = $objectManager->create('Magento\Checkout\Model\Session')->getLastRealOrder();
echo $orderObj->getEntityId(); //Entity Id
echo $orderObj->getIncrementId(); //Increment Id

Note : Don't use object manager directly