DEV: Update transformers in topic-list/item

These will enable discourse/discourse-topic-thumbnails#60

Author: davidtaylorhq

app/assets/javascripts/discourse/app/components/topic-list/item.gjs

@@ -6,7 +6,7 @@ import didInsert from "@ember/render-modifiers/modifiers/did-insert";
 import { next } from "@ember/runloop";
 import { service } from "@ember/service";
 import { modifier } from "ember-modifier";
-import { eq } from "truth-helpers";
+import { eq, not } from "truth-helpers";
 import PluginOutlet from "discourse/components/plugin-outlet";
 import PostCountOrBadges from "discourse/components/topic-list/post-count-or-badges";
 import TopicExcerpt from "discourse/components/topic-list/topic-excerpt";
@@ -185,6 +185,18 @@ export default class Item extends Component {
     }
   }
 
+  get useMobileLayout() {
+    return applyValueTransformer(
+      "topic-list-item-mobile-layout",
+      this.site.mobileView,
+      { topic: this.args.topic }
+    );
+  }
+
+  get useDesktopLayout() {
+    return !this.useMobileLayout;
+  }
+
   <template>
     <tr
       {{! template-lint-disable no-invalid-interactive }}
@@ -210,15 +222,15 @@ export default class Item extends Component {
         (if @topic.closed "closed")
         this.tagClassNames
         (applyValueTransformer
-          "topic-list-item-class" (array) (hash topic=@topic)
+          "topic-list-item-class" (array) (hash topic=@topic index=@index)
         )
       }}
     >
       <PluginOutlet
         @name="above-topic-list-item"
         @outletArgs={{hash topic=@topic}}
       />
-      {{#if this.site.desktopView}}
+      {{#if this.useDesktopLayout}}
         {{#each @columns as |entry|}}
           <entry.value.item
             @topic={{@topic}}

app/assets/javascripts/discourse/app/lib/transformer/registry.js

@@ -19,5 +19,7 @@ export const VALUE_TRANSFORMERS = Object.freeze([
   "small-user-attrs",
   "topic-list-columns",
   "topic-list-header-sortable-column",
+  "topic-list-class",
   "topic-list-item-class",
+  "topic-list-item-mobile-layout",
 ]);