New API for defining field type categories

A module can define field type categories in a MODULE_NAME.field_type_categories.yml file contained in the module's base directory.

Each plugin has the following structure:

CATEGORY_NAME:
   label: STRING
   description: STRING
   weight: INTEGER
   libraries:
     - STRING

Setting the field type category as a translatable label in annotation is deprecated:

Before

/**
 * @FieldType(
 *   id = "decimal",
 *   label = @Translation("Number (decimal)"),
 *   ...
 *   category = @Translation("Number"),
 * )
 */
class DecimalItem extends NumericItemBase { ... }

After

/**
 * @FieldType(
 *   id = "decimal",
 *   label = @Translation("Number (decimal)"),
 *   ...
 *   category = "number",
 * )
 */
class DecimalItem extends NumericItemBase { ... }

Where number is the category ID defined in core.field_type_categories.yml:

...
number:
  label: 'Number'
  description: 'Field to store number. I.e. id, price, or quantity.'
  weight: -40
  libraries:
    - module_name/library_name

...

The library allows loading assets within the Field UI when the categories are displayed. This allows the category to provide an icon for itself:

.field-icon-number {
  background-image: url("...");
}

BC layer

Your module can add a backwards compatibility layer for Drupal 10.1 and previous versions by adding the following hook implementation to your .module file.

use  Drupal\Core\StringTranslation\TranslatableMarkup;

// ...

/**
 * Implements hook_field_info_alter().
 *
 * @todo Remove once minimum version supported is at least 10.2.0.
 */
function MODULE_NAME_field_info_alter(array &$info): void {
  // Allow module to work with versions of older versions of Drupal.
  if (\version_compare(\Drupal::VERSION, '10.1.9999', '<')) {
    // @todo Replace 'decimal' with the field type and "Number" with the previous category string.
    $info['decimal']['category'] = new TranslatableMarkup("Number");
  }
}

The field type category info can be accessed with the help of the plugin methods getLabel(), getDescription(), and getWeight(), etc. These methods are available on the plugin instances retrieved using the YAML-based plugin discovery system.