Exclude If Blank

Here’s a more fully formed version of the ExcludeIfBlank extension from the previous section.

It works just like the built-in exclude_if_nil option, but checks for blank? instead. It checks the Blueprint options first, then allows fields to override it.

class ExcludeIfBlankExtension < Blueprinter::Extension
  # @param ctx [Blueprinter::V2::Context::Field]
  def around_field_value(ctx)
    val = yield ctx

    exclude = ctx.blueprint.options[:exclude_if_blank]
    exclude = ctx.field.options[:exclude_if_blank] if ctx.field.options.key? :exclude_if_blank
    skip! if exclude && val.blank?

    val
  end
end

Add it to your ApplicationBlueprint and use it in your blueprints.

class ApplicationBlueprint < Blueprinter::V2::Base
  add ExcludeIfBlankExtension.new
end

class WidgetBlueprint < ApplicationBlueprint
  field :name
  field :description, exclude_if_blank: true
end

class CategoryBlueprint < ApplicationBlueprint
  set :exclude_if_blank, true

  field :name, exclude_if_blank: false
  field :description
end