Php – How to check for null in Twig

PHPshort-circuitingtwig

What construct should I use to check whether a value is NULL in a Twig template?

Best Answer

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 %}