Is it still possible to switch Drupal themes in Storybook?

I've looked into the services.yml of cl_server and storybook.

There's still the theme.negotiator.storybook, which facilitates the theme switch. I just needed to fix the route name:

diff --git a/storybook/src/Theme/StorybookThemeNegotiator.php b/storybook/src/Theme/StorybookThemeNegotiator.php
index 7288b43212..dff64b8c92 100644
--- a/storybook/src/Theme/StorybookThemeNegotiator.php
+++ b/storybook/src/Theme/StorybookThemeNegotiator.php
@@ -42,7 +42,7 @@ public function applies(RouteMatchInterface $route_match): bool {
       return FALSE;
     }
     $theme = $this->getTheme();
-    return ($route_name === 'storybook.render' && !empty($theme));
+    return ($route_name === 'storybook.render_story' && !empty($theme));
   }
 
   /**

I can now get the render route to use a specific theme by adding the query param _drupalTheme=MY_THEME_NAME, like
/storybook/stories/render/{hash}?_drupalTheme=MY_THEME_NAME.

The question is: how to we get the information, which theme should be used into Storybook.js ? Do we need a Storybook.js extension like the @lullabot/storybook-drupal-addon or can we add an option/meta to our stories which theme could be used?

Maybe @e0ipso can point me in the right direction?

@arnalyse thanks for this fix. It allows to select a different theme from the site default theme like this:

# .storybook/preview.js

/** @type { import('@storybook/server').Preview } */
const preview = {
  globals: {
    _drupalTheme: 'my_theme',
  },
  parameters: {
...

Great. That allows for explicitely setting the theme 👍

Do you also know how to get the theme selector from the lullabot module?

Otherwise I would ask in the Lullabot Github repository if there are any plans to rewrite their addon to work alongside the new Drupal Storybook module …

Hi @arnalyse, I think it should be possible to roll your own using this

https://github.com/Lullabot/storybook-drupal-addon/blob/8a6690e09f6471b9...

and this https://github.com/Lullabot/storybook-drupal-addon/blob/main/src/manager.ts together with the guide on writing plugins

The folks at lullabot and e0ipso might be better at helping with this

Pushed the quickfix from #3 into a PR thus marking this issue as NR.