How to check for null in Twig?
php, short-circuiting, twig
Solution
Depending on what exactly you need:
- `is null` checks whether the value is `null`:
{% if var is null %}
{# do something #}
{% endif %}
- `is defined` checks whether the variable is defined:
{% if var is not defined %}
{# do something #}
{% endif %}
Additionally the `is sameas` test, which does a type strict comparison of two values, might be of interest for checking values other than `null` (like `false`):
{% if var is sameas(false) %}
{# do something %}
{% endif %}
Problem
What construct should I use to check whether a value is NULL in a Twig template?