Hides some data in milestone filter dropdown

Selects milestone value in dropdown

app/assets/javascripts/boards/components/boards_selector.js

@@ -90,7 +90,14 @@ require('./board_new_form');
       },
     },
     created() {
+      const $milestoneDropdown = $('.dropdown-menu-milestone');
+
       this.state.currentBoard = this.currentBoard;
+
+      if (this.currentBoard.milestone_id) {
+        $milestoneDropdown.find('.dropdown-input').hide();
+        $milestoneDropdown.find('.dropdown-footer').hide();
+      }
     },
   });
 })();

app/views/shared/issuable/_filter.html.haml

@@ -28,7 +28,7 @@
             placeholder: "Search assignee", data: { any_user: "Any Assignee", first_user: current_user.try(:username), null_user: true, current_user: true, project_id: @project.try(:id), selected: params[:assignee_id], field_name: "assignee_id", default_label: "Assignee" } })
 
         .filter-item.inline.milestone-filter
-          = render "shared/issuable/milestone_dropdown", selected: finder.milestones.try(:first), name: :milestone_title, show_any: true, show_upcoming: true
+          = render "shared/issuable/milestone_dropdown", selected: finder.milestones.try(:first), name: :milestone_title, show_any: true, show_upcoming: true, board: board
 
         .filter-item.inline.labels-filter
           = render "shared/issuable/label_dropdown", selected: finder.labels.select(:title).uniq, use_id: false, selected_toggle: params[:label_name], data_options: { field_name: "label_name[]" }

app/views/shared/issuable/_milestone_dropdown.html.haml

 - project = @target_project || @project
 - extra_class = extra_class || ''
 - show_menu_above = show_menu_above || false
+- board = local_assigns.fetch(:board, nil)
+- board_has_milestone = board.try(:milestone).present?
+- selected = local_assigns.fetch(:selected, nil)
+
+- if board_has_milestone
+  - selected = board.milestone
+
 - selected_text = selected.try(:title) || params[:milestone_title]
 - dropdown_title = local_assigns.fetch(:dropdown_title, "Filter by milestone")
 - if selected.present? || params[:milestone_title].present?