How to retrieve all Variables from a Twig Template?
UPDATE 2019
Although {{ dump() }}
does work, in some circumstances it may result in a "memory exhausted" error from PHP if it generates too much information (for example, due to recursion). In this case, try {{ dump(_context|keys) }}
to get a list of the defined variables by name without dumping their contents.
UPDATE 2017
It is possible by using {{ dump() }}
filter. Thanks for pointing that out in the comments!
OUTDATED
It is not possible.
You can look for these variable in twig templates and add |default('your_value')
filter to them. It will check if variable is defined and is not empty, and if no - will replace it with your value.
The way I do it is
<script>console.log({{ _context | json_encode | raw }});</script>
And then I just check my console using DevTools
This is useful I find to get all the top-level keys available in the current context:
<ol>
{% for key, value in _context %}
<li>{{ key }}</li>
{% endfor %}
</ol>
Thanks to https://www.drupal.org/node/1906780