Storybook: Add internal stories functionality (#23139)

contribute/style-guides/storybook.md

@@ -10,7 +10,7 @@ Storybook is:
 
 ## How to create stories
 
-Stories for a component should be placed next to the component file. The Storybook file requires the same name as the component file. For example, a story for `SomeComponent.tsx` will have the file name `SomeComponent.story.tsx`.
+Stories for a component should be placed next to the component file. The Storybook file requires the same name as the component file. For example, a story for `SomeComponent.tsx` will have the file name `SomeComponent.story.tsx`. If a story should be internal, not visible in production, name the file `SomeComponent.story.internal.tsx`.
 
 ### Writing stories
 

packages/grafana-ui/.storybook/main.ts

+const stories = ['../src/**/*.story.{js,jsx,ts,tsx,mdx}'];
+
+if (process.env.NODE_ENV !== 'production') {
+  stories.push('../src/**/*.story.internal.{js,jsx,ts,tsx,mdx}');
+}
+
 module.exports = {
-  stories: ['../src/**/*.story.{js,jsx,ts,tsx,mdx}'],
+  stories: stories,
   addons: [
     '@storybook/addon-knobs',
     '@storybook/addon-actions',