Tutorial

Let's look at the following two lines:

{{ content.field_tags }}
{{ node.field_tags }}

The difference between these two lines is that in the first case we have the Tags field as a rendered array, and in the second case we have this field as an object.

You can use the first line in your template to print out the Tags field. But in some cases you might want to print out a field from the node directly. If you put the second line in your node template, you will get an error:

Object of type Drupal\Core\Field\EntityReferenceFieldItemList cannot be printed

You cannot print an object just like that. You can if you call the view() method on that object:

{{ node.field_tags.view() }}

But this is not allowed by default. Drupal 8 comes with the Twig Sandbox Policy and by default the view() method is blacklisted. In order to whitelist this method you must edit your settings.php file and add the following lines:

$settings['twig_sandbox_whitelisted_methods'] = [
  'id',
  'label',
  'bundle',
  'get',
  '__toString',
  'toString',
  'referencedEntities',
  'view',
];

If you don't want to whitelist any method that is by default blacklisted, or if editing the settings.php file is not an option, and you want to print field in a template you need another solution.

You can use the "Twig Render This" module which provides a simple Twig filter. After you install this module you can use the following syntax in your template:

{{ node.field_tags | renderThis }}

If you want to use a specific display mode you can use the following syntax:

{{ node.field_tags | renderThis('teaser') }}

If you do not provide the display mode, the filter will use the default mode.

This filter can be especially useful in your Views templates. For example you might be listing node teasers in a View, and then you can use the following code to print out View fields:

{% for row in rows %}
  {{ row.content['#node'].field_svg | renderThis }}
{% endfor %}

You can also use this filter to render entities. In some cases this might be useful. For example, if for some reason you need to render the first row in a View using the default display mode, and all other rows using the teaser mode, you would write something like this:

{% for row in rows %}
  {% if loop.index == 1 %}
    {{ row.content['#node'] | renderThis('default') }}
  {% else %}
    {{ row.content['#node'] | renderThis('teaser') }}
  {% endif %}
{% endfor %}