I’m using WooCommerce v3.2.6 and WordPress 4.9.1.
I’ve added an endpoint to the WooCommerce myaccount area (view-subscription):

function my_custom_endpoints() {
    add_rewrite_endpoint( 'view-subscription', EP_ROOT | EP_PAGES );
}

add_action( 'init', 'my_custom_endpoints' );

function my_custom_query_vars( $vars ) {
    $vars[] = 'view-subscription';
    return $vars;
}

add_filter( 'query_vars', 'my_custom_query_vars', 0 );

function view_subscription_endpoint_content() {
    include get_template_directory().'/woocommerce/myaccount/view-subscription.php'; 
}

add_action( 'woocommerce_account_view-subscription_endpoint', 'view_subscription_endpoint_content' );

The endpoint is working but I want to be able to pass the ID of a subscription (a post type) to the endpoint (similar to how view-order works). How can I do this?

eg.

myaccount/view-order/21313 - Displays details of order #21313
myaccount/view-subscription/35464 - I want this to display the details of the subscription post #35464.

If I go to the above URL myaccount/view-subscription/35464 , the view-subscription.php template is still loading, but what is the best way to access the ID, 35464, from the URL?