Merge pull request #253 from seanpdoyle/tag-helper-in-previews

Make `TagHelper` available in Previews

CHANGELOG.md

@@ -1,5 +1,17 @@
 # master
 
+* Make `ActionView::Helpers::TagHelper` available in Previews
+
+    def with_html_content
+      render(MyComponent.new) do
+        tag.div do
+          content_tag(:span, "Hello")
+        end
+      end
+    end
+
+    *Sean Doyle*
+
 # v1.14.1
 
 * Fix bug where generator created invalid test code.

README.md

@@ -291,11 +291,28 @@ class TestComponentPreview < ViewComponent::Preview
   def with_long_title
     render(TestComponent.new(title: "This is a really long title to see how the component renders this"))
   end
+
+  def with_content_block
+    render(TestComponent.new(title: "This component accepts a block of content") do
+      tag.div do
+        content_tag(:span, "Hello")
+      end
+    end
+  end
 end
 ```
 
-Which generates <http://localhost:3000/rails/components/test_component/with_default_title>
-and <http://localhost:3000/rails/components/test_component/with_long_title>.
+Which generates <http://localhost:3000/rails/components/test_component/with_default_title>,
+<http://localhost:3000/rails/components/test_component/with_long_title>,
+and <http://localhost:3000/rails/components/test_component/with_content_block>.
+
+The `ViewComponent::Preview` base class includes
+[`ActionView::Helpers::TagHelper`][tag-helper], which provides the [`tag`][tag]
+and [`content_tag`][content_tag] view helper methods.
+
+[tag-helper]: https://api.rubyonrails.org/classes/ActionView/Helpers/TagHelper.html
+[tag]: https://api.rubyonrails.org/classes/ActionView/Helpers/TagHelper.html#method-i-tag
+[content_tag]: https://api.rubyonrails.org/classes/ActionView/Helpers/TagHelper.html#method-i-content_tag
 
 Previews default to the application layout, but can be overridden:
 
@@ -413,6 +430,11 @@ Bug reports and pull requests are welcome on GitHub at https://github.com/github
 |@blakewilliams|
 |Boston, MA|
 
+|<img src="https://avatars.githubusercontent.com/seanpdoyle?s=256" alt="seanpdoyle" width="128" />|
+|:---:|
+|@seanpdoyle|
+|New York, NY|
+
 ## License
 
 The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).

lib/view_component/preview.rb

@@ -4,6 +4,7 @@
 
 module ViewComponent # :nodoc:
   class Preview
+    include ActionView::Helpers::TagHelper
     extend ActiveSupport::DescendantsTracker
 
     def render(component, **args, &block)

test/test/components/previews/preview_component_preview.rb

@@ -12,4 +12,8 @@ def without_cta
   def with_content
     render(PreviewComponent.new(title: "title")) { "some content" }
   end
+
+  def with_tag_helper_in_content
+    render(PreviewComponent.new(title: "title")) { content_tag(:span, "some content") }
+  end
 end

test/view_component/integration_test.rb

@@ -145,6 +145,12 @@ class IntegrationTest < ActionDispatch::IntegrationTest
     assert_includes response.body, "some content"
   end
 
+  test "renders preview component with tag helper-generated content preview" do
+    get "/rails/components/preview_component/with_tag_helper_in_content"
+
+    assert_includes response.body, "<span>some content</span>"
+  end
+
   test "renders badge component open preview" do
     get "/rails/components/issues/badge_component/open"