FIX: correctly sorts public channels (#19555)

plugins/chat/assets/javascripts/discourse/services/chat-channels-manager.js

@@ -86,10 +86,12 @@ export default class ChatChannelsManager extends Service {
   }
 
   get publicMessageChannels() {
-    return this.channels.filter(
-      (channel) =>
-        channel.isCategoryChannel && channel.currentUserMembership.following
-    );
+    return this.channels
+      .filter(
+        (channel) =>
+          channel.isCategoryChannel && channel.currentUserMembership.following
+      )
+      .sort((a, b) => a.title.localeCompare(b.title));
   }
 
   get directMessageChannels() {

plugins/chat/spec/system/list_channels/mobile_spec.rb

@@ -31,6 +31,23 @@ RSpec.describe "List channels | mobile", type: :system, js: true, mobile: true d
       end
     end
 
+    context "when multiple category channels are present" do
+      fab!(:channel_1) { Fabricate(:category_channel, name: "b channel") }
+      fab!(:channel_2) { Fabricate(:category_channel, name: "a channel") }
+
+      before do
+        channel_1.add(current_user)
+        channel_2.add(current_user)
+      end
+
+      it "sorts them alphabetically" do
+        visit("/chat")
+
+        expect(page.find("#public-channels a:nth-child(1)")["data-chat-channel-id"]).to eq(channel_2.id.to_s)
+        expect(page.find("#public-channels a:nth-child(2)")["data-chat-channel-id"]).to eq(channel_1.id.to_s)
+      end
+    end
+
     context "when direct message channels" do
       fab!(:dm_channel_1) { Fabricate(:direct_message_channel, users: [current_user]) }
       fab!(:inaccessible_dm_channel_1) { Fabricate(:direct_message_channel) }

plugins/chat/spec/system/list_channels/no_sidebar_spec.rb

@@ -32,6 +32,23 @@ RSpec.describe "List channels | no sidebar", type: :system, js: true do
       end
     end
 
+    context "when multiple category channels are present" do
+      fab!(:channel_1) { Fabricate(:category_channel, name: "b channel") }
+      fab!(:channel_2) { Fabricate(:category_channel, name: "a channel") }
+
+      before do
+        channel_1.add(current_user)
+        channel_2.add(current_user)
+      end
+
+      it "sorts them alphabetically" do
+        visit("/chat")
+
+        expect(page.find("#public-channels a:nth-child(1)")["data-chat-channel-id"]).to eq(channel_2.id.to_s)
+        expect(page.find("#public-channels a:nth-child(2)")["data-chat-channel-id"]).to eq(channel_1.id.to_s)
+      end
+    end
+
     context "when direct message channels" do
       fab!(:dm_channel_1) { Fabricate(:direct_message_channel, users: [current_user]) }
       fab!(:inaccessible_dm_channel_1) { Fabricate(:direct_message_channel) }

plugins/chat/spec/system/list_channels/sidebar_spec.rb

@@ -41,6 +41,23 @@ RSpec.describe "List channels | sidebar", type: :system, js: true do
       end
     end
 
+    context "when multiple category channels are present" do
+      fab!(:channel_1) { Fabricate(:category_channel, name: "b channel") }
+      fab!(:channel_2) { Fabricate(:category_channel, name: "a channel") }
+
+      before do
+        channel_1.add(current_user)
+        channel_2.add(current_user)
+      end
+
+      it "sorts them alphabetically" do
+        visit("/")
+
+        expect(page.find("#sidebar-section-content-chat-channels li:nth-child(1)")).to have_css(".channel-#{channel_2.id}")
+        expect(page.find("#sidebar-section-content-chat-channels li:nth-child(2)")).to have_css(".channel-#{channel_1.id}")
+      end
+    end
+
     context "when direct message channels" do
       fab!(:dm_channel_1) { Fabricate(:direct_message_channel, users: [current_user]) }
       fab!(:inaccessible_dm_channel_1) { Fabricate(:direct_message_channel) }