Add helper to use view transition

Author: Intrepidd

app/helpers/turbo/drive_helper.rb

@@ -43,6 +43,13 @@ def turbo_page_requires_reload
     provide :head, turbo_page_requires_reload_tag
   end
 
+  # Configure whether to use the View Transitions API when navigating to a new page.
+  # See +turbo_use_view_transition_tag+.
+  def turbo_use_view_transition
+    provide :head, turbo_use_view_transition_tag
+  end
+
+
   # See +turbo_page_requires_reload+.
   def turbo_page_requires_reload_tag
     tag.meta(name: "turbo-visit-control", content: "reload")
@@ -83,5 +90,10 @@ def turbo_refresh_scroll_tag(scroll = :reset)
     raise ArgumentError, "Invalid scroll option '#{scroll}'" unless scroll.in?(%i[ reset preserve ])
     tag.meta(name: "turbo-refresh-scroll", content: scroll)
   end
+
+  # See +turbo_use_view_transition+.
+  def turbo_use_view_transition_tag
+    tag.meta(name: "view-transition", content: "same-origin")
+  end
 end
 

test/drive/drive_helper_test.rb

@@ -16,6 +16,11 @@ class Turbo::DriveHelperTest < ActionDispatch::IntegrationTest
     assert_match(/<meta name="turbo-refresh-method" content="morph">/, @response.body)
     assert_match(/<meta name="turbo-refresh-scroll" content="preserve">/, @response.body)
   end
+
+  test "using view transition" do
+    get trays_path
+    assert_match(/<meta name="view-transition" content="same-origin">/, @response.body)
+  end
 end
 
 class Turbo::DriverHelperUnitTest < ActionView::TestCase

test/dummy/app/views/trays/index.html.erb

@@ -1,5 +1,6 @@
 <% turbo_exempts_page_from_cache %>
 <% turbo_page_requires_reload %>
 <%= turbo_refreshes_with method: :morph, scroll: :preserve %>
+<%= turbo_use_view_transition %>
 
 <p>Not in the cache!</p>