FEATURE: Conditionally force optimized category style (#29473)

The `categories_only_optimized` category page style has been introduced
in commit d37a0d401c. This commit makes
sure that style is enforced for users who can see over 1000 categories
in order to keep `/categories` page functional.

app/assets/javascripts/discourse/app/components/discovery/categories-display.gjs

@@ -12,6 +12,7 @@ import ConditionalLoadingSpinner from "discourse/components/conditional-loading-
 import LoadMore from "discourse/components/load-more";
 import PluginOutlet from "discourse/components/plugin-outlet";
 import SubcategoriesWithFeaturedTopics from "discourse/components/subcategories-with-featured-topics";
+import { MAX_UNOPTIMIZED_CATEGORIES } from "discourse/lib/constants";
 
 const mobileCompatibleViews = [
   "categories_with_featured_topics",
@@ -57,15 +58,22 @@ export default class CategoriesDisplay extends Component {
     return component;
   }
 
-  get #globalComponent() {
+  get style() {
     let style = this.siteSettings.desktop_category_page_style;
     if (this.site.mobileView && !mobileCompatibleViews.includes(style)) {
       style = mobileCompatibleViews[0];
     }
-    const component = globalComponents[style];
+    if (this.site.categories.length > MAX_UNOPTIMIZED_CATEGORIES) {
+      style = "categories_only_optimized";
+    }
+    return style;
+  }
+
+  get #globalComponent() {
+    const component = globalComponents[this.style];
     if (!component) {
       // eslint-disable-next-line no-console
-      console.error("Unknown category list style: " + style);
+      console.error("Unknown category list style: " + this.style);
       return CategoriesOnly;
     }
 
@@ -87,8 +95,7 @@ export default class CategoriesDisplay extends Component {
     return (
       this.args.loadMore &&
       (this.site.lazy_load_categories ||
-        this.siteSettings.desktop_category_page_style ===
-          "categories_only_optimized")
+        this.style === "categories_only_optimized")
     );
   }
 

app/assets/javascripts/discourse/app/lib/constants.js

@@ -97,3 +97,5 @@ export const SITE_SETTING_REQUIRES_CONFIRMATION_TYPES = {
   simple: "simple",
   user_option: "user_option",
 };
+
+export const MAX_UNOPTIMIZED_CATEGORIES = 1000;

app/assets/javascripts/discourse/app/routes/discovery-categories.js

@@ -2,6 +2,7 @@ import { action } from "@ember/object";
 import { service } from "@ember/service";
 import { hash } from "rsvp";
 import { ajax } from "discourse/lib/ajax";
+import { MAX_UNOPTIMIZED_CATEGORIES } from "discourse/lib/constants";
 import PreloadStore from "discourse/lib/preload-store";
 import { defaultHomepage } from "discourse/lib/utilities";
 import Category from "discourse/models/category";
@@ -21,8 +22,11 @@ export default class DiscoveryCategoriesRoute extends DiscourseRoute {
   async findCategories(parentCategory) {
     let model;
 
-    const style =
+    let style =
       this.site.desktopView && this.siteSettings.desktop_category_page_style;
+    if (this.site.categories.length > MAX_UNOPTIMIZED_CATEGORIES) {
+      style = "categories_only_optimized";
+    }
 
     if (
       style === "categories_and_latest_topics" ||

app/models/category_list.rb

@@ -4,6 +4,9 @@ class CategoryList
   CATEGORIES_PER_PAGE = 20
   SUBCATEGORIES_PER_CATEGORY = 5
 
+  # Maximum number of categories before the optimized category page style is enforced
+  MAX_UNOPTIMIZED_CATEGORIES = 1000
+
   include ActiveModel::Serialization
 
   cattr_accessor :preloaded_topic_custom_fields
@@ -139,9 +142,14 @@ class CategoryList
       query = query.where(parent_category_id: @options[:parent_category_id])
     end
 
+    style =
+      if Category.secured(@guardian).count > MAX_UNOPTIMIZED_CATEGORIES
+        "categories_only_optimized"
+      else
+        SiteSetting.desktop_category_page_style
+      end
     page = [1, @options[:page].to_i].max
-    if SiteSetting.desktop_category_page_style == "categories_only_optimized" ||
-         @guardian.can_lazy_load_categories?
+    if style == "categories_only_optimized" || @guardian.can_lazy_load_categories?
       query = query.limit(CATEGORIES_PER_PAGE).offset((page - 1) * CATEGORIES_PER_PAGE)
     elsif page > 1
       # Pagination is supported only when lazy load is enabled. If it is not,

lib/tasks/javascript.rake

@@ -160,9 +160,11 @@ task "javascript:update_constants" => :environment do
 
     export const TOPIC_VISIBILITY_REASONS = #{Topic.visibility_reasons.to_json};
 
-    export const SYSTEM_FLAG_IDS = #{PostActionType.types.to_json}
+    export const SYSTEM_FLAG_IDS = #{PostActionType.types.to_json};
 
-    export const SITE_SETTING_REQUIRES_CONFIRMATION_TYPES = #{SiteSettings::TypeSupervisor::REQUIRES_CONFIRMATION_TYPES.to_json}
+    export const SITE_SETTING_REQUIRES_CONFIRMATION_TYPES = #{SiteSettings::TypeSupervisor::REQUIRES_CONFIRMATION_TYPES.to_json};
+
+    export const MAX_UNOPTIMIZED_CATEGORIES = #{CategoryList::MAX_UNOPTIMIZED_CATEGORIES};
   JS
 
   pretty_notifications = Notification.types.map { |n| "  #{n[0]}: #{n[1]}," }.join("\n")