Field extra field blocks

8. Field & Extra Field Blocks

When to Use

When exposing entity field data or extra fields (pseudo-fields) as blocks in Layout Builder layouts.

Items

FieldBlock Plugin

Description: Derivative block plugin that exposes entity fields as blocks

Plugin ID Format: field_block:{entity_type}:{bundle}:{field_name}

Configuration: | Key | Type | Description | |-----|------|-------------| | label_display | string | '0' (hidden) or '1' (visible) | | formatter | mapping | Field formatter configuration (type, label, settings) | | context_mapping | mapping | Maps entity context to block |

Example:

configuration:
  id: 'field_block:node:article:field_image'
  label_display: '0'
  context_mapping:
    entity: 'layout_builder.entity'
  formatter:
    label: hidden
    type: responsive_image
    settings:
      responsive_image_style: wide
    third_party_settings: {}

Usage:

$component = new SectionComponent(
  \Drupal::service('uuid')->generate(),
  'content',
  [
    'id' => 'field_block:node:article:body',
    'label_display' => '0',
    'context_mapping' => ['entity' => 'layout_builder.entity'],
    'formatter' => [
      'label' => 'hidden',
      'type' => 'text_default',
      'settings' => [],
      'third_party_settings' => [],
    ],
  ]
);

Gotchas: - Field must exist on entity_type/bundle or block breaks - Formatter settings same structure as view display component - Block respects field access — won't render if user can't view field - Empty fields with no default value don't render (access check fails) - Enabling Layout Builder auto-converts existing fields to field blocks in default section

ExtraFieldBlock Plugin

Description: Derivative block plugin for extra fields (pseudo-fields like node links, author info)

Plugin ID Format: extra_field_block:{entity_type}:{bundle}:{extra_field_name}

Configuration: | Key | Type | Description | |-----|------|-------------| | label_display | string | '0' or '1' | | context_mapping | mapping | Maps entity context |

Example:

configuration:
  id: 'extra_field_block:node:article:links'
  label_display: '0'
  context_mapping:
    entity: 'layout_builder.entity'

Common Extra Fields: - links — Node edit/delete links - display_submitted — Author and date info - Module-provided extra fields (e.g., flag module adds flag links)

Gotchas: - Extra fields defined by hook_entity_extra_field_info() - Not real fields — no field storage, just render arrays - Configuration simpler than field blocks (no formatter)

Field Block Availability

Description: Which fields become available as field blocks

Automatic Discovery: - Layout Builder scans entity_type/bundle for fields - Only configurable display fields become blocks - Base fields (title, created, etc.) included if configurable

Customization:

// Limit field blocks in layout builder
function mymodule_layout_builder_field_block_alter(array &$definitions) {
  // Remove specific field block
  unset($definitions['field_block:node:article:field_internal']);

  // Modify field block label
  if (isset($definitions['field_block:node:article:body'])) {
    $definitions['field_block:node:article:body']['admin_label'] = 'Article Content';
  }
}

Gotchas: - All configurable display fields exposed by default (can overwhelm editors) - Use Layout Builder Restrictions module to limit available blocks - Removing field from entity doesn't immediately remove field block (cached definitions)

Field Formatter Integration

Description: Field blocks use field formatter plugins for rendering

Formatter Configuration:

'formatter' => [
  'label' => 'above',        // above, hidden, inline, visually_hidden
  'type' => 'image',         // Formatter plugin ID
  'settings' => [            // Formatter-specific settings
    'image_style' => 'large',
    'image_link' => 'content',
  ],
  'third_party_settings' => [],  // Module extensions
]

Changing Formatter: - Via UI: Layout Builder block configuration form provides formatter selector - Via code: Modify formatter array in component configuration

Gotchas: - Formatter must be applicable to field type - Invalid formatter falls back to default or causes error - Third-party settings from modules like field_group carry over

Common Mistakes

Wrong derivative format → Must be field_block:entity_type:bundle:field_name exactly. Typos = block doesn't exist
Missing context mapping → Field blocks REQUIRE entity context. Without it, no entity to get field data from
Assuming all fields available → Only configurable display fields. Computed fields, non-display fields excluded unless custom code exposes them
Not handling field access → Field blocks respect field access. Protected fields won't render for unprivileged users, no error shown
Mixing up field blocks and inline blocks → Field blocks display entity field data. Inline blocks are custom block content. Completely different plugins
Forgetting formatter settings → Missing or invalid formatter config can break rendering. Always validate formatter exists for field type
Not restricting field blocks → All fields exposed by default. Use Layout Builder Restrictions or alter hooks to prevent editor overwhelm