12.12.2025 | Michael Ebert

Render field with given formatter type programmatically

my_module.module
$field_render_array = $entity->{$field_name}->view([
  'type' => 'default_formatter', // Replace with desired formatter type.
  'label' => 'hidden', // If you want to hide the label of the field (optional).
  'settings' => [
    'trim_length' => 100, // Example for textfields: Trim the text to 100 characters.
  ],
]);

Issue:

You want to print out a field in a given formatter type.

Solution:

An easy way would be to use the configuration on the view display of your entity and select the wanted field formatter there. But in some cases (e.g. you don't want to render the field on the node where it is defined) this does not work.

This snippet shows you how to do it programmatically (for example in a preprocess hook). 

As fields themselves do not have a `view()` method, we need to manipulate the render array of a field item list you get when loading an entity.

field values
fields

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23.10.2026 | Lothar Ferreira Neumann

How to fill empty form fields via a custom Drupal AJAX command

SetValueIfEmptyCommand.php
<?php

declare(strict_types=1);

namespace Drupal\my_module\Ajax;

use Drupal\Core\Ajax\CommandInterface;

/**
 * Ajax command: fill empty form elements with a predefined value.
 *
 * This command targets one or more form elements via a CSS selector and sets
 * their value only if the current value is empty (after trimming).
 *
 * The command also triggers `input` and `change` events so Drupal behaviors and
 * other listeners react as if the user entered the value manually.
 */
final class SetValueIfEmptyCommand implements CommandInterface {

  /**
   * The Ajax command name used by Drupal.AjaxCommands.
   */
  public const COMMAND = 'setValueIfEmpty';

  /**
   * Default selector used when none is provided.
   */
  public const DEFAULT_SELECTOR = '[data-my-fill-target]';

  /**
   * Creates a command instance.
   *
   * @param string $fillValue
   *   The value to set when the target element is empty.
   * @param string|null $targetSelector
   *   CSS selector for the target elements. If omitted, DEFAULT_SELECTOR is used.
   */
  public function __construct(
    protected string $fillValue,
    protected ?string $targetSelector = null,
  ) {}

  /**
   * {@inheritdoc}
   */
  public function render(): array {
    return [
      'command' => self::COMMAND,
      'selector' => $this->targetSelector ?? self::DEFAULT_SELECTOR,
      'value' => $this->fillValue,
    ];
  }

}
media_fill_if_empty.js
/**
 * @file Field empty check.
 */
(function (Drupal) {
  'use strict';

  Drupal.AjaxCommands.prototype.setValueIfEmpty = function (ajax, response) {
    const targetSelector = response && response.selector ? response.selector : '';
    const fillValue = response && typeof response.value === 'string' ? response.value : '';

    if (!targetSelector) {
      return;
    }

    const elements = document.querySelectorAll(targetSelector);
    for (const element of elements) {
      let currentValue = '';

      if (typeof element.value === 'string') {
        currentValue = element.value.trim();
      }
      else if (element.isContentEditable) {
        currentValue = (element.textContent || '').trim();
      }

      if (currentValue !== '') {
        continue;
      }

      if (typeof element.value === 'string') {
        element.value = fillValue;
      }
      else if (element.isContentEditable) {
        element.textContent = fillValue;
      }
      else {
        continue;
      }

      element.dispatchEvent(new Event('input', { bubbles: true }));
      element.dispatchEvent(new Event('change', { bubbles: true }));
    }
  };

})(Drupal);
my_module.libraries.yml
set_value_if_empty:
  js:
    js/set_value_if_empty.js: {}
  dependencies:
    - core/drupal
    - core/drupal.ajax
MyResponse.php
use Drupal\Core\Ajax\AjaxResponse;
use Drupal\my_module\Ajax\SetValueIfEmptyCommand;

$response = new AjaxResponse();

// Example: fill a media name field if it's empty.
$fill_value = 'foo-bar';

// Selector for a specific element in this use-case.
$target_selector = '[data-drupal-selector$="my_field"]';

$response->addAttachments([
  'library' => [
    'my_module/set_value_if_empty',
  ],
]);

$response->addCommand(new SetValueIfEmptyCommand($fill_value, $target_selector));

return $response;
php
js
yml / yaml
media
ajax
field values
12.02.2026 | Michael Ebert

Get value of an entity field

entity_field_value.php
// For single value fields.
$entity->field_name->value;

// If you don`t know the main property.
$main_property_name = $entity->field_name->getMainPropertyName();

// For multiple value fields.
$entity->field_name->getValue();
php
field values
entities