if_undefined¶
- Module: mod_base
Tests if a value is undefined, returning the given argument.
Whereas the |default filter also falls back to the default value when a value is an empty string or false, this filter only falls to its value when it is undefined.
This can be used for setting values which default to true if they are never set.
For example:
{% if value|if_undefined:`true` %}The value is true or undefined{% endif %}
When the value is undefined then the output “The value was undefined”.
See also
