Change Link Name on Generated Link Field - drupal

Question

I'm creating a custom theme in Drupal 8 and on the node.html.twig template I'm using {{content.field_type}} to display the link of the category which the current page is in to allow the user to link back to the list of pages in that category. Using this, the page renders:
Sub Cat Name
What do I need to do change this to:
My Custom Link

Answer 1

It's possible to change render arrays using preprocess functions, but in your case it's not a good idea. Link you are talking about is a result of rendering of field formatter. So, you just need another field formatter for your 'Type' field, instead of current 'Label' formatter.
Creating new formatter is quite easy(especially if you use EntityReferenceLabelFormatter as an example). Suppose you have a module called entity_reference_link_formatter. Then in the directory of this module create src/Plugin/Field/FieldFormatter folder and put there the following EntityReferenceLinkFormatter.php file:
<?php
/**
* #file
* Contains Drupal\entity_reference_link_formatter\Plugin\Field\FieldFormatter\EntityReferenceLinkFormatter
*/
namespace Drupal\entity_reference_link_formatter\Plugin\Field\FieldFormatter;
use Drupal\Core\Entity\Exception\UndefinedLinkTemplateException;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Field\Plugin\Field\FieldFormatter\EntityReferenceFormatterBase;
use Drupal\Core\Form\FormStateInterface;
/**
* Plugin implementation of the 'entity reference link' formatter.
*
* #FieldFormatter(
* id = "entity_reference_link",
* label = #Translation("Link"),
* description = #Translation("Display the link to the referenced entity."),
* field_types = {
* "entity_reference"
* }
* )
*/
class EntityReferenceLinkFormatter extends EntityReferenceFormatterBase {
/**
* {#inheritdoc}
*/
public static function defaultSettings() {
return [
'text' => 'View',
] + parent::defaultSettings();
}
/**
* {#inheritdoc}
*/
public function settingsForm(array $form, FormStateInterface $form_state) {
$elements['text'] = [
'#title' => t('Text of the link to the referenced entity'),
'#type' => 'textfield',
'#required' => true,
'#default_value' => $this->getSetting('text'),
];
return $elements;
}
/**
* {#inheritdoc}
*/
public function settingsSummary() {
$summary = [];
$summary[] = t('Link text: #text', ['#text' => $this->getSetting('text')]);
return $summary;
}
/**
* {#inheritdoc}
*/
public function viewElements(FieldItemListInterface $items, $langcode) {
$elements = array();
foreach ($this->getEntitiesToView($items, $langcode) as $delta => $entity) {
if (!$entity->isNew()) {
try {
$uri = $entity->urlInfo();
$elements[$delta] = [
'#type' => 'link',
'#title' => t('!text', ['!text' => $this->getSetting('text')]),
'#url' => $uri,
'#options' => $uri->getOptions(),
];
if (!empty($items[$delta]->_attributes)) {
$elements[$delta]['#options'] += array('attributes' => array());
$elements[$delta]['#options']['attributes'] += $items[$delta]->_attributes;
// Unset field item attributes since they have been included in the
// formatter output and shouldn't be rendered in the field template.
unset($items[$delta]->_attributes);
}
}
catch (UndefinedLinkTemplateException $e) {
// This exception is thrown by \Drupal\Core\Entity\Entity::urlInfo()
// and it means that the entity type doesn't have a link template nor
// a valid "uri_callback", so don't bother trying to output a link for
// the rest of the referenced entities.
}
}
$elements[$delta]['#cache']['tags'] = $entity->getCacheTags();
}
return $elements;
}
}
After enabling this module (or after clearing the cache if this module was enabled earlier), you will have 'Link' formatter for all your 'Entity reference' fields, allowing you to customize link text just in the formatter settings.