Telemetry: Count play function usage

code/lib/core-server/src/utils/StoryIndexGenerator.ts

@@ -38,6 +38,7 @@ type SpecifierStoriesCache = Record<Path, CacheEntry>;
 
 export const AUTODOCS_TAG = 'autodocs';
 export const STORIES_MDX_TAG = 'stories-mdx';
+export const PLAY_FN_TAG = 'play-fn';
 
 /** Was this docs entry generated by a .mdx file? (see discussion below) */
 export function isMdxEntry({ tags }: DocsIndexEntry) {

code/lib/core-server/src/utils/summarizeIndex.ts

@@ -1,6 +1,6 @@
 import type { StoryIndex } from '@storybook/types';
 
-import { STORIES_MDX_TAG, isMdxEntry, AUTODOCS_TAG } from './StoryIndexGenerator';
+import { STORIES_MDX_TAG, isMdxEntry, AUTODOCS_TAG, PLAY_FN_TAG } from './StoryIndexGenerator';
 
 const PAGE_REGEX = /(page|screen)/i;
 
@@ -9,6 +9,7 @@ export const isPageStory = (storyId: string) => PAGE_REGEX.test(storyId);
 export function summarizeIndex(storyIndex: StoryIndex) {
   let storyCount = 0;
   let pageStoryCount = 0;
+  let playStoryCount = 0;
   let autodocsCount = 0;
   let storiesMdxCount = 0;
   let mdxCount = 0;
@@ -18,19 +19,23 @@ export function summarizeIndex(storyIndex: StoryIndex) {
       if (isPageStory(entry.title)) {
         pageStoryCount += 1;
       }
+      if (entry.tags?.includes(PLAY_FN_TAG)) {
+        playStoryCount += 1;
+      }
     } else if (entry.type === 'docs') {
       if (isMdxEntry(entry)) {
         mdxCount += 1;
-      } else if (entry.tags.includes(STORIES_MDX_TAG)) {
+      } else if (entry.tags?.includes(STORIES_MDX_TAG)) {
         storiesMdxCount += 1;
-      } else if (entry.tags.includes(AUTODOCS_TAG)) {
+      } else if (entry.tags?.includes(AUTODOCS_TAG)) {
         autodocsCount += 1;
       }
     }
   });
   return {
     storyCount,
     pageStoryCount,
+    playStoryCount,
     autodocsCount,
     storiesMdxCount,
     mdxCount,

code/lib/csf-tools/src/CsfFile.test.ts

@@ -866,4 +866,104 @@ describe('CsfFile', () => {
       ).toThrow('CSF: Expected tag to be string literal');
     });
   });
+
+  describe('play functions', () => {
+    it('story csf2', () => {
+      expect(
+        parse(
+          dedent`
+          export default { title: 'foo/bar', tags: ['X'] };
+          export const A = () => {};
+          A.play = () => {};
+          A.tags = ['Y'];
+        `
+        )
+      ).toMatchInlineSnapshot(`
+        meta:
+          title: foo/bar
+          tags:
+            - X
+        stories:
+          - id: foo-bar--a
+            name: A
+            tags:
+              - 'Y'
+              - play-fn
+      `);
+    });
+
+    it('story csf3', () => {
+      expect(
+        parse(
+          dedent`
+          export default { title: 'foo/bar', tags: ['X'] };
+          export const A = {
+            render: () => {},
+            play: () => {},
+            tags: ['Y'],
+          };
+        `
+        )
+      ).toMatchInlineSnapshot(`
+        meta:
+          title: foo/bar
+          tags:
+            - X
+        stories:
+          - id: foo-bar--a
+            name: A
+            tags:
+              - 'Y'
+              - play-fn
+      `);
+    });
+
+    it('meta csf2', () => {
+      expect(
+        parse(
+          dedent`
+          export default { title: 'foo/bar', play: () => {}, tags: ['X'] };
+          export const A = {
+            render: () => {},
+            tags: ['Y'],
+          };
+        `
+        )
+      ).toMatchInlineSnapshot(`
+        meta:
+          title: foo/bar
+          tags:
+            - X
+            - play-fn
+        stories:
+          - id: foo-bar--a
+            name: A
+            tags:
+              - 'Y'
+      `);
+    });
+
+    it('meta csf3', () => {
+      expect(
+        parse(
+          dedent`
+          export default { title: 'foo/bar', play: () => {}, tags: ['X'] };
+          export const A = () => {};
+          A.tags = ['Y'];
+        `
+        )
+      ).toMatchInlineSnapshot(`
+        meta:
+          title: foo/bar
+          tags:
+            - X
+            - play-fn
+        stories:
+          - id: foo-bar--a
+            name: A
+            tags:
+              - 'Y'
+      `);
+    });
+  });
 });

code/lib/csf-tools/src/CsfFile.ts

@@ -454,6 +454,9 @@ export class CsfFile {
     // default export can come at any point in the file, so we do this post processing last
     const entries = Object.entries(self._stories);
     self._meta.title = this._makeTitle(self._meta.title);
+    if (self._metaAnnotations.play) {
+      self._meta.tags = [...(self._meta.tags || []), 'play-fn'];
+    }
     self._stories = entries.reduce((acc, [key, story]) => {
       if (isExportStory(key, self._meta)) {
         const id = toId(self._meta.id || self._meta.title, storyNameFromExport(key));
@@ -466,13 +469,16 @@ export class CsfFile {
           parameters.docsOnly = true;
         }
         acc[key] = { ...story, id, parameters };
-        const { tags } = self._storyAnnotations[key];
+        const { tags, play } = self._storyAnnotations[key];
         if (tags) {
           const node = t.isIdentifier(tags)
             ? findVarInitialization(tags.name, this._ast.program)
             : tags;
           acc[key].tags = parseTags(node);
         }
+        if (play) {
+          acc[key].tags = [...(acc[key].tags || []), 'play-fn'];
+        }
       }
       return acc;
     }, {} as Record<string, StaticStory>);

code/lib/store/template/stories/component-play.stories.ts

@@ -0,0 +1,23 @@
+import { global as globalThis } from '@storybook/global';
+import type { PartialStoryFn, PlayFunctionContext, StoryContext } from '@storybook/types';
+import { within } from '@storybook/testing-library';
+import { expect } from '@storybook/jest';
+
+export default {
+  component: globalThis.Components.Pre,
+  play: async ({ canvasElement, name }: PlayFunctionContext) => {
+    await expect(JSON.parse(within(canvasElement).getByTestId('pre').innerText)).toEqual({
+      name,
+    });
+  },
+  // Render the story name into the Pre
+  decorators: [
+    (storyFn: PartialStoryFn, context: StoryContext) => {
+      const { name } = context;
+      return storyFn({ args: { object: { name } } });
+    },
+  ],
+};
+
+export const StoryOne = {};
+export const StoryTwo = {};