Published: April 25, 2018
Showing Fields in a Referenced Node Depending on the Value of a Boolean in a Paragraph Bundle
Mission: you have 2 fields in a Drupal paragraph bundle, one a node reference field and one a boolean field. Show certain fields in the referenced node depending on the value of the boolean field.
That's a question that popped up today in the DrupalTwig Slack. Here's my response, which I implemented a version of recently. (In that particular case, we had an 'Event' content type with fields for 'address', 'phone number', etc and also a reference field for 'Amenity'. If the fields were filled in in the event content type, they were to be presented, but if they were left blank on the event content type, we had to pull in the corresponding fields for address, phone number, etc from the referenced amenity.) Anyway, my response:
{# Check the value of the boolean field #}
{% if paragraph.field_boolean.value === 'on' %}
{# Just render the title of the referenced node #}
{{ paragraph.field_reference.0.entity.label }}
{% else %}
{# Render the title and the image field #}
{{ paragraph.field_reference.0.entity.label }}
<img src="{{ file_url(paragraph.field_reference.0.entity.field_image.url) }}" alt="{{ paragraph.field_reference.0.entity.field_image.url }}">
{% endif %}
{# Ensure that the cache contexts can bubble up by rendering the {{ content }} variable #}
{{ content|without('field_boolean', 'field_reference') }}
Just for clarity - variables in that code snippet are simply made up off the top of my head (this is what happens when answering questions on Slack). I'm sure I have things slightly wrong and you'll need to play with them to get them to work correctly.
Also, the reason for the cache contexts bit? Say thanks to Lee Rowlands from Previous Next for his blog post Ensuring Drupal 8 Block Cache Tags bubble up to the Page