From 73d207a56873625dedda8889b539f9c46663ef6b Mon Sep 17 00:00:00 2001
From: Joffrey JAFFEUX <j.jaffeux@gmail.com>
Date: Wed, 14 Oct 2020 16:29:40 +0200
Subject: [PATCH] DEV: load styleguide assets only when needed (#10918)

---
 .../javascripts/discourse/app/lib/url.js      |  1 +
 plugins/styleguide/plugin.rb                  |  6 +++++
 .../spec/integration/assets_spec.rb           | 24 +++++++++++++++++++
 3 files changed, 31 insertions(+)
 create mode 100644 plugins/styleguide/spec/integration/assets_spec.rb

diff --git a/app/assets/javascripts/discourse/app/lib/url.js b/app/assets/javascripts/discourse/app/lib/url.js
index c5ecda5d67e..335f33cd1c6 100644
--- a/app/assets/javascripts/discourse/app/lib/url.js
+++ b/app/assets/javascripts/discourse/app/lib/url.js
@@ -34,6 +34,7 @@ const SERVER_SIDE_ONLY = [
   /^\/admin\/logs\/watched_words\/action\/[^\/]+\/download$/,
   /^\/pub\//,
   /^\/invites\//,
+  /^\/styleguide\//,
 ];
 
 // The amount of height (in pixles) that we factor in when jumpEnd is called so
diff --git a/plugins/styleguide/plugin.rb b/plugins/styleguide/plugin.rb
index 47a5d7cfc8a..2e0703359cd 100644
--- a/plugins/styleguide/plugin.rb
+++ b/plugins/styleguide/plugin.rb
@@ -13,3 +13,9 @@ load File.expand_path('../lib/styleguide/engine.rb', __FILE__)
 Discourse::Application.routes.append do
   mount ::Styleguide::Engine, at: '/styleguide'
 end
+
+after_initialize do
+  register_asset_filter do |type, request|
+    request&.fullpath&.start_with?('/styleguide')
+  end
+end
diff --git a/plugins/styleguide/spec/integration/assets_spec.rb b/plugins/styleguide/spec/integration/assets_spec.rb
new file mode 100644
index 00000000000..562730b7dd1
--- /dev/null
+++ b/plugins/styleguide/spec/integration/assets_spec.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'Styleguide assets' do
+  before do
+    SiteSetting.styleguide_enabled = true
+    sign_in(Fabricate(:admin))
+  end
+
+  context 'visits homepage' do
+    it 'doesn’t load styleguide assets' do
+      get '/'
+      expect(response.body).to_not include('styleguide')
+    end
+  end
+
+  context 'visits styleguide' do
+    it 'loads styleguide assets' do
+      get '/styleguide'
+      expect(response.body).to include('styleguide')
+    end
+  end
+end