Functions in Twig templates

Twig provides a number of handy functions that can be used directly within Templates.

List of Twig Functions

Drupal core adds a handful of custom functions that are Drupal-specific. These are defined in the TwigExtension class.

You can also define your own custom Twig functions in a custom module (but not in a theme). To find an example of how to do this, see this example in core/modules/system/tests/modules/twig_extension_test/src/TwigExtension/TestExtension.php.

attach_library($library)

Attaches an asset library to the template.

{{ attach_library('classy/node') }}

active_theme()

Prints the machine name of the active theme.

{{ active_theme() }} {# my_custom_theme #}

active_theme_path()

Prints the relative path to the active theme.

{{ active_theme_path() }} {# themes/custom/my_custom_theme #}

create_attribute($attributes)

Create new Attribute objects using the create_attribute() function inside a Twig template. These objects can then be manipulated like other Attribute objects coming into the Twig template.

{% set my_attribute = create_attribute() %}
{%
  set my_classes = [
    'kittens',
    'llamas',
    'puppies',
  ]
%}
<div{{ my_attribute.addClass(my_classes).setAttribute('id', 'myUniqueId') }}>
  {{ content }}
</div>

<div{{ create_attribute({'class': ['region', 'region--header']}) }}>
  {{ content }}
</div>

render_var($arg)

Convenience function around render().

{{ render_var({ '#theme': 'foo_bar', '#title': 'baz' }) }}

file_url($uri)

This helper function accepts a URI to a file and creates a relative URL path to the file.

{{ file_url(node.field_example_image.entity.uri.value) }}

link($text, $uri, $attributes)

This helper function accepts as the first parameter the text and as the second parameter the URI. The optional third parameter is the attributes object that can be used to provide eg. additional CSS classes.

Note that this function handles the <nolink> and <button> options of Drupal menu item text and generates <span> or <button> element instead of <a> when they are used. It also adds a data-drupal-link-system-path attribute and an is-active CSS class (in case the link is active) automatically if the URI parameter is a \Drupal\Core\Url object with its set_active_class option set to TRUE!

Examples:

{{ link(item.title, item.uri, create_attribute({'class': ['foo', 'bar', 'baz']})) }}

Old, shorthand implementation using an array for $attributes:

{{ link(item.title, item.uri, { 'class':['foo', 'bar', 'baz']} ) }}

(Still supported, but not recommended Drupal > 8.3, see above and https://www.drupal.org/node/2818293)

path($name, $parameters, $options)

Generates a [relative] URL path given a route name and parameters.

{# Link to frontpage view. #}
<a href="{{ path('view.frontpage.page_1') }}">{{ 'View all content'|t }}</a>

{# Link to user entity/profile page. #}
<a href="{{ path('entity.user.canonical', {'user': user.id}) }}">{{ 'View user profile'|t }}</a>

{# Link to node page. #}
<a href="{{ path('entity.node.canonical', {'node': node.id}) }}">{{ 'View node page'|t }}</a>

{# Link to taxonomy term. #}
<a href="{{ path('entity.taxonomy_term.canonical', {'taxonomy_term': term.id}) }}">{{ 'View taxonomy term'|t }}</a>

{# Add a destination query parameter. Simple Example #}
<a href="{{ path('user.login', {}, {'query': {'destination': path('<current>') }}) }}">{{ 'View node page'|t }}</a>.

{# Add a destination query parameter. Advanced Example, event_user_sync.registration is a custom route from a custom module with the name event_user_sync #}
{% set redirect_path = path('event_user_sync.registration', {'node': node.id}) %}
<a href="{{ path('user.register',{},{'query':{'destination': redirect_path }}) }}">{{ 'Register'|t }}</a>

The url and path function are defined in close parallel to those found in \Symfony\Bridge\Twig\Extension\RoutingExtension.

url($name, $parameters, $options)

Generate an absolute URL given a route name and parameters:

<a href="{{ url('view.frontpage.page_1') }}">{{ 'View all content'|t }}</a>

Generate an absolute URL to the current URL:

<a href="{{ url('<current>') }}">{{ 'Reload'|t }}</a>

Generate an absolute URL to the front page:

<a href="{{ url('<front>') }}">{{ 'Home'|t }}</a>

Generate an absolute URL to a specific node:

<a href="{{ url('entity.node.canonical', { 'node': 123 }) }}">{{ 'Visit node 123'|t }}</a>

Generate an absolute URL to a specific taxonomy term:

<a href="{{ url('entity.taxonomy_term.canonical', { 'taxonomy_term': 123 }) }}">{{ 'Visit taxonomy term 123'|t }}</a>

If you are working in a node template and have a node variable available, you can generate an absolute URL to the current node:

<a href="{{ url('entity.node.canonical', { 'node': node.id() }) }}">{{ 'Visit this page'|t }}</a>