How to display an empty tv field MODX REVO?

Question

PHP

There is a simple snippet that gets the value of the tv fields:

$where = array (
    'contentid' => $resourceId, // id ресурса
    'tmplvarid' => $variableId // id поля
);

$tv = $modx->getObject('modTemplateVarResource', $where); // получение tv.объекта
$val = $tv->get('value'); // получение значения

return $val;

But, if these fields are not filled in the resource, then an error like this appears:
Fatal error: Call to a member function get() on null in /home/.../www/core/cache/includes/elements/modsnippet/6. include.cache.php on line 19
How can I get around this? It is necessary that in some cases the fields could be empty, i.e. empty.
MODX REVO 2.5.5
PHP 5.6

Answer 1

thanks for the idea qork
Rewrote the snippet:

$where = array (
    'contentid' => $resourceId, // id ресурса
    'tmplvarid' => $variableId // id поля
);


$tv = $modx->getObject('modTemplateVarResource', $where); // получение tv.объекта

if(!$tv) return;


$val = $tv->get('value'); // получение значения

return $val;

Answer 2

if(!$resourceId || !$variableId) return;