Extension points for topic list on discovery page

app/assets/javascripts/discourse/controllers/discovery/topics.js.es6

@@ -25,6 +25,9 @@ const controllerOpts = {
     this.setProperties({ order: "default", ascending: false });
   },
 
+  // Overwrite this to perform client side filtering of topics, if desired
+  filteredTopics: Ember.computed.alias('model.topics'),
+
   actions: {
 
     changeSort(sortBy) {

app/assets/javascripts/discourse/templates/discovery/topics.hbs

@@ -32,6 +32,12 @@
   {{/if}}
 
   {{#if hasTopics}}
+
+    {{plugin-outlet
+      name="discovery-before-topic-list"
+      tagName=""
+      args=(hash model=model category=category)}}
+
     {{topic-list
       highlightLastVisited=true
       top=top
@@ -48,7 +54,7 @@
       expandGloballyPinned=expandGloballyPinned
       expandAllPinned=expandAllPinned
       category=category
-      topics=model.topics}}
+      topics=filteredTopics}}
   {{/if}}
 {{/discovery-topics-list}}