Add Append StyleSheet Pack Tag Helper

README.md

@@ -249,36 +249,42 @@ While this also generally applies to `stylesheet_pack_tag`, you may use multiple
 <%= stylesheet_pack_tag 'print', media: 'print' %>
 ```
 
-#### View Helper `append_javascript_pack_tag`
+#### View Helper `append_javascript_pack_tag` and `append_stylesheet_pack_tag`
 
-If you need configure your pack names from the view for a route or partials, then you will need some logic to ensure you call the helpers only once with multiple arguments. The new view helper `append_javascript_pack_tag` can solve this problem. This helper will queue up packs when the `javascript_pack_tag` is finally used.
+If you need configure your script pack names or stylesheet pack names from the view for a route or partials, then you will need some logic to ensure you call the helpers only once with multiple arguments. The new view helpers, `append_javascript_pack_tag` and `append_stylesheet_pack_tag` can solve this problem. The helper `append_javascript_pack_tag` will queue up script packs when the `javascript_pack_tag` is finally used. Similarly,`append_stylesheet_pack_tag` will queue up style packs when the `stylesheet_pack_tag` is finally used.
 
 Main view:
 ```erb
 <% append_javascript_pack_tag 'calendar' %>
+<% append_stylesheet_pack_tag 'calendar' %>
 ```
 
 Some partial:
 ```erb
 <% append_javascript_pack_tag 'map' %>
+<% append_stylesheet_pack_tag 'map' %>
 ```
 
 And the main layout has:
 ```erb
 <%= javascript_pack_tag 'application' %>
+<%= stylesheet_pack_tag 'application' %>
 ```
 
 is the same as using this in the main layout:
 
 ```erb
 <%= javascript_pack_tag 'calendar', 'map', application' %>
+<%= stylesheet_pack_tag 'calendar', 'map', application' %>
 ```
 
 However, you typically can't do that in the main layout, as the view and partial codes will depend on the route.
 
-Thus, you can distribute the logic of what packs are needed for any route. All the magic of splitting up the code was automatic!
+Thus, you can distribute the logic of what packs are needed for any route. All the magic of splitting up the code and CSS was automatic!
 
 **Important:** `append_javascript_pack_tag` can be used anywhere in your application as long as it is executed BEFORE the `javascript_pack_tag`. If you attempt to call `append_javascript_pack_tag` helper after `javascript_pack_tag`, an error will be raised. You should have only a single `javascript_pack_tag` invocation in your page load.
+
+**Important** Similar to `append_javascript_pack_tag`, the `append_stylesheet_pack_tag` should be used anywhere in your application as long as it is executed BEFORE the `stylesheet_pack_tag`. However, if you attempt to call `append_stylesheet_pack_tag` helper after `stylesheet_pack_tag`, an error will be **NOT** be raised.
 
 The typical issue is that your layout might reference some partials that need to configure packs. A good way to solve this problem is to use `content_for` to ensure that the code to render your partial comes before the call to `javascript_pack_tag`.
 

lib/webpacker/helper.rb

@@ -158,7 +158,27 @@ def preload_pack_asset(name, **options)
   def stylesheet_pack_tag(*names, **options)
     return "" if Webpacker.inlining_css?
 
-    stylesheet_link_tag(*sources_from_manifest_entrypoints(names, type: :stylesheet), **options)
+    if @stylesheet_pack_tag_loaded
+      puts "To prevent duplicated stylesheet on the page, you should call stylesheet_pack_tag only once on the page. " \
+      "Please refer to https://github.com/shakacode/shakapacker/blob/master/README.md#usage for the usage guide"
+    end
+
+    requested_packs = sources_from_manifest_entrypoints(names, type: :stylesheet)
+    appended_packs = available_sources_from_manifest_entrypoints(@stylesheet_pack_tag_queue || [], type: :stylesheet)
+
+    @stylesheet_pack_tag_loaded = true
+
+    stylesheet_link_tag(*(requested_packs | appended_packs), **options)
+  end
+
+  def append_stylesheet_pack_tag(*names)
+    if @stylesheet_pack_tag_loaded
+      raise "You can only call append_stylesheet_pack_tag before stylesheet_pack_tag helper. " \
+      "Please refer to https://github.com/shakacode/shakapacker/blob/master/README.md#usage for the usage guide"
+    end
+
+    @stylesheet_pack_tag_queue ||= []
+    @stylesheet_pack_tag_queue.concat names
   end
 
   def append_javascript_pack_tag(*names, defer: true)
@@ -184,6 +204,10 @@ def sources_from_manifest_entrypoints(names, type:)
       names.map { |name| current_webpacker_instance.manifest.lookup_pack_with_chunks!(name.to_s, type: type) }.flatten.uniq
     end
 
+    def available_sources_from_manifest_entrypoints(names, type:)
+      names.map { |name| current_webpacker_instance.manifest.lookup_pack_with_chunks(name.to_s, type: type) }.flatten.compact.uniq
+    end
+
     def resolve_path_to_image(name, **options)
       path = name.starts_with?("static/") ? name : "static/#{name}"
       path_to_asset(current_webpacker_instance.manifest.lookup!(path), options)

test/helper_test.rb

@@ -204,5 +204,50 @@ def test_stylesheet_pack_tag_multiple_invocations_are_allowed
     assert_equal \
       hello_stimulus_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk) }.join("\n"),
       stimulus_style
+
+    assert_nothing_raised do
+      stylesheet_pack_tag(:application)
+      stylesheet_pack_tag(:hello_stimulus)
+    end
+  end
+
+  def test_stylesheet_pack_with_append
+    append_stylesheet_pack_tag(:hello_stimulus)
+
+    assert_equal \
+      (application_stylesheet_chunks + hello_stimulus_stylesheet_chunks).uniq.map { |chunk| stylesheet_link_tag(chunk) }.join("\n"),
+      stylesheet_pack_tag(:application)
+  end
+
+  def test_stylesheet_pack_with_duplicate_append
+    append_stylesheet_pack_tag(:hello_stimulus)
+    append_stylesheet_pack_tag(:application)
+
+    assert_equal \
+      (application_stylesheet_chunks + hello_stimulus_stylesheet_chunks).uniq.map { |chunk| stylesheet_link_tag(chunk) }.join("\n"),
+      stylesheet_pack_tag(:application)
+  end
+
+  def test_multiple_stylesheet_pack_with_different_media_attr
+    app_style = stylesheet_pack_tag(:application)
+    app_style_with_media = stylesheet_pack_tag(:application, media: "print")
+    hello_stimulus_style_with_media = stylesheet_pack_tag(:hello_stimulus, media: "all")
+
+    assert_equal \
+      application_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk) }.join("\n"),
+      app_style
+
+    assert_equal \
+      application_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk, media: "print") }.join("\n"),
+      app_style_with_media
+
+    assert_equal \
+      hello_stimulus_stylesheet_chunks.map { |chunk| stylesheet_link_tag(chunk, media: "all") }.join("\n"),
+      hello_stimulus_style_with_media
+
+    assert_nothing_raised do
+      stylesheet_pack_tag(:application)
+      stylesheet_pack_tag(:application, media: "print")
+    end
   end
 end