Extra Field
This module allows developers to create custom fields that can be added to entity display and form modes. These "extra fields" do not store data but can be used to format existing entity data for display or add custom markup and fields to entity forms.
Provides plugin types to add extra fields in entity view and entity form of fieldable entities.
With ExtraFieldDisplay plugins developers can add custom output to entity view modes. Extra fields are treated like regular fields, site builders can place them in entity view modes, the output is rendered in twig templates. Extra fields typically combine entity data and format it for display. Extra fields do not store data and do not have a field widget.
With ExtraFieldForm plugins (8.x-2.x only) developers can add custom fields or markup to entity forms. Site builders can place them in entity form modes. Extra fields do not store data. Extra form fields can be used as replacement for hook_form_alter.
The included extra_field_example module contains ready to use example plugins. Copy them to your custom module and modify them to your needs.
Know limitation: ExtraFieldForm plugins can not be used for paragraphs, inline entity forms, blocks in layout builder. See details in this issue.
Other modules
- Extra Field Plus module: Provides an interface for Extra Field display settings.
- Markup module: To add fixed markup to forms and view modes.
- Twig markup module: To display content using twig syntax on forms and view modes.