Remove unnecessary partial and move render conditions to component

app/components/blacklight/facet_field_filter_component.rb

@@ -1,25 +1,6 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldFilterComponent < Blacklight::Component
-    def initialize(facet_field:)
-      @facet_field = facet_field
-    end
-
-    def render?
-      @facet_field.facet_field.index_range.any?
-    end
-
-    def prefix
-      @facet_field.paginator.prefix
-    end
-
-    def clear_facet_prefix_url
-      @facet_field.paginator.params_for_resort_url('index', @facet_field.search_state.to_h.except(@facet_field.paginator.request_keys[:prefix]))
-    end
-
-    def facet_prefix_url(letter)
-      @facet_field.paginator.params_for_resort_url('index', @facet_field.search_state.to_h.merge(@facet_field.paginator.request_keys[:prefix] => letter))
-    end
-  end
+  class FacetFieldFilterComponent < Facets::IndexNavigationComponent; end
+  FacetFieldFilterComponent = ActiveSupport::Deprecation::DeprecatedConstantProxy.new("FacetFieldFilterComponent", "Blacklight::Facets::IndexNavigationComponent", ActiveSupport::Deprecation.new)
 end

app/components/blacklight/facets/filters_component.html.erb

@@ -1,4 +1,4 @@
   <div class="<%= classes %>">
     <%= render Blacklight::Facets::SuggestComponent.new(presenter: presenter) %>
-    <%= render 'facet_index_navigation' if render_index_navigation? %>
+    <%= render Blacklight::Facets::IndexNavigationComponent.new(presenter: presenter) %>
   </div>

app/components/blacklight/facet_field_filter_component.html.erb → app/components/blacklight/facets/index_navigation_component.html.erb

@@ -3,7 +3,7 @@
     <li class="page-item <%= 'active' if prefix.blank? %>">
       <%= link_to t('blacklight.search.facets.all'), clear_facet_prefix_url, data: { blacklight_modal: "preserve" }, class: 'page-link' %>
     </li>
-    <% @facet_field.facet_field.index_range.each do |letter| %>
+    <% index_range.each do |letter| %>
       <li class="page-item <%= 'active' if prefix == letter %>">
         <%= link_to(letter, facet_prefix_url(letter), class: 'page-link', data: { blacklight_modal: "preserve" }) %>
       </li>

app/components/blacklight/facets/index_navigation_component.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module Blacklight
+  module Facets
+    class IndexNavigationComponent < Blacklight::Component
+      # @params [Blacklight::FacetFieldPresenter] presenter
+      def initialize(presenter:)
+        @presenter = presenter
+      end
+
+      def render?
+        index_range && @presenter.display_facet.index?
+      end
+
+      def index_range
+        @presenter.facet_field.index_range
+      end
+
+      def prefix
+        @presenter.paginator.prefix
+      end
+
+      def clear_facet_prefix_url
+        @presenter.paginator.params_for_resort_url('index', @presenter.search_state.to_h.except(@presenter.paginator.request_keys[:prefix]))
+      end
+
+      def facet_prefix_url(letter)
+        @presenter.paginator.params_for_resort_url('index', @presenter.search_state.to_h.merge(@presenter.paginator.request_keys[:prefix] => letter))
+      end
+    end
+  end
+end

app/controllers/concerns/blacklight/catalog.rb

@@ -79,6 +79,7 @@ def track
 
   # displays values and pagination links for a single facet field
   def facet
+    # @facet is a Blacklight::Configuration::FacetField
     @facet = blacklight_config.facet_fields[params[:id]]
     raise ActionController::RoutingError, 'Not Found' unless @facet
 
@@ -87,8 +88,10 @@ def facet
                 else
                   search_service.facet_field_response(@facet.key)
                 end
+    # @display_facet is a Blacklight::Solr::Response::Facets::FacetField
     @display_facet = @response.aggregations[@facet.field]
 
+    # @presenter is a Blacklight::FacetFieldPresenter
     @presenter = @facet.presenter.new(@facet, @display_facet, view_context)
     @pagination = @presenter.paginator
     respond_to do |format|

spec/components/blacklight/facets/index_navigation_component_spec.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+RSpec.describe Blacklight::Facets::IndexNavigationComponent, type: :component do
+  let(:pagination) { Blacklight::Solr::FacetPaginator.new([]) }
+  let(:facet) { Blacklight::Configuration::FacetField.new(index_range: '0'..'9', presenter: Blacklight::FacetFieldPresenter) }
+  let(:display_facet) { instance_double(Blacklight::Solr::Response::Facets::FacetField, items: [], offset: 0, prefix: '', sort: 'index', index?: true) }
+  let(:blacklight_config) { Blacklight::Configuration.new }
+
+  let(:presenter) { facet.presenter.new(facet, display_facet, vc_test_controller.view_context) }
+
+  before do
+    with_request_url "/catalog/facet/language" do
+      render_inline(described_class.new(presenter: presenter))
+    end
+  end
+
+  it 'renders the facet index navigation range' do
+    expect(page).to have_css '.pagination'
+    expect(page).to have_link '0', href: '/catalog/facet/language.html?facet.prefix=0&facet.sort=index'
+    expect(page).to have_link '1'
+    expect(page).to have_link '8'
+    expect(page).to have_link '9'
+  end
+
+  it 'renders an "all" button' do
+    expect(page).to have_css '.page-link', text: 'All'
+  end
+
+  context 'with a selected index' do
+    let(:display_facet) { instance_double(Blacklight::Solr::Response::Facets::FacetField, items: [], offset: 0, prefix: '5', sort: 'index', index?: true) }
+
+    it 'highlights the selected index' do
+      expect(page).to have_css '.active', text: '5'
+    end
+
+    it 'enables the clear facets button' do
+      expect(page).to have_link 'All'
+    end
+  end
+end