Fallback 'display name' for optional belongs_to associations

What would you like to be able to do? Can you provide some examples?

Recently, I ran into the following use case:

In the index and show pages of a resource that has an optional belongs to association, display a customizable fallback string (i.e 'none'), when the associated record is not present.

For example, in the index page of a Book that optionally belongs to an Author, display Anonymous if there isn't an associated author.

Is there already a way to achieve this with Field::BelongsTo without having to generate and modify the default views of the field/resource?

How could we go about implementing that?

If possible, having an option (fallback_display_name or similar) that can be passed to Field::BelongsTo to be displayed in the views when the association is not present.

  # app/dashboards/book_dashboard.rb

  ATTRIBUTE_TYPES = {
    author: Field::BelongsTo.with_options(fallback_display_name: 'Anonymous'),
  }

• Can you think of other approaches to the problem?

Having a custom field OptionalBelongsTo < Field::BelongsTo that supports the mentioned behavior.

require 'administrate/field/belongs_to'

class OptionalBelongsTo < Administrate::Field::BelongsTo
  def display_associated_resource
    data.present? ? super : options.fetch(:fallback_display_name, "")
  end
end

Start by reading Field::BelongsTo and the example app/dashboards/book_dashboard.rb configuration, then trace how display_associated_resource is used by the default views. The work is done when an optional association can show a configurable fallback such as “Anonymous” without modifying generated field or resource views.