Angular: Add random attribute to bootstrapped selector

code/frameworks/angular/src/client/angular-beta/AbstractRenderer.ts

@@ -3,7 +3,8 @@ import { bootstrapApplication } from '@angular/platform-browser';
 
 import { BehaviorSubject, Subject } from 'rxjs';
 import { stringify } from 'telejson';
-import { ICollection, Parameters, StoryFnAngularReturnType } from '../types';
+
+import { ICollection, StoryFnAngularReturnType } from '../types';
 import { getApplication } from './StorybookModule';
 import { storyPropsProvider } from './StorybookProvider';
 import { componentNgModules } from './StorybookWrapperComponent';
@@ -16,6 +17,14 @@ type StoryRenderInfo = {
 
 const applicationRefs = new Map<HTMLElement, ApplicationRef>();
 
+/**
+ * Attribute name for the story UID that may be written to the targetDOMNode.
+ *
+ * If a target DOM node has a story UID attribute, it will be used as part of
+ * the selector for the Angular component.
+ */
+export const STORY_UID_ATTRIBUTE = 'data-sb-story-uid';
+
 export abstract class AbstractRenderer {
   /**
    * Wait and destroy the platform
@@ -122,10 +131,17 @@ export abstract class AbstractRenderer {
 
     const analyzedMetadata = new PropertyExtractor(storyFnAngular.moduleMetadata, component);
 
+    const storyUid = targetDOMNode.getAttribute(STORY_UID_ATTRIBUTE);
+    const componentSelector = storyUid !== null ? `${targetSelector}[${storyUid}]` : targetSelector;
+    if (storyUid !== null) {
+      const element = targetDOMNode.querySelector(targetSelector);
+      element.toggleAttribute(storyUid, true);
+    }
+
     const application = getApplication({
       storyFnAngular,
       component,
-      targetSelector,
+      targetSelector: componentSelector,
       analyzedMetadata,
     });
 
@@ -161,8 +177,10 @@ export abstract class AbstractRenderer {
     return storyIdIsInvalidHtmlTagName ? `sb-${id.replace(invalidHtmlTag, '')}-component` : id;
   }
 
+  /**
+   * Adds DOM element that angular will use as bootstrap component.
+   */
   protected initAngularRootElement(targetDOMNode: HTMLElement, targetSelector: string) {
-    // Adds DOM element that angular will use as bootstrap component
     // eslint-disable-next-line no-param-reassign
     targetDOMNode.innerHTML = '';
     targetDOMNode.appendChild(document.createElement(targetSelector));

code/frameworks/angular/src/client/angular-beta/DocsRenderer.ts

@@ -1,6 +1,8 @@
 import { addons } from '@storybook/preview-api';
 import { DOCS_RENDERED, STORY_CHANGED } from '@storybook/core-events';
-import { AbstractRenderer } from './AbstractRenderer';
+
+import { getNextStoryUID } from './utils/StoryUID';
+import { AbstractRenderer, STORY_UID_ATTRIBUTE } from './AbstractRenderer';
 import { StoryFnAngularReturnType, Parameters } from '../types';
 
 export class DocsRenderer extends AbstractRenderer {
@@ -45,4 +47,13 @@ export class DocsRenderer extends AbstractRenderer {
   async afterFullRender(): Promise<void> {
     await AbstractRenderer.resetCompiledComponents();
   }
+
+  protected override initAngularRootElement(
+    targetDOMNode: HTMLElement,
+    targetSelector: string
+  ): void {
+    super.initAngularRootElement(targetDOMNode, targetSelector);
+
+    targetDOMNode.setAttribute(STORY_UID_ATTRIBUTE, getNextStoryUID(targetDOMNode.id));
+  }
 }

code/frameworks/angular/src/client/angular-beta/RendererFactory.test.ts

@@ -13,11 +13,13 @@ describe('RendererFactory', () => {
   let rendererFactory: RendererFactory;
   let rootTargetDOMNode: HTMLElement;
   let rootDocstargetDOMNode: HTMLElement;
+  let storyInDocstargetDOMNode: HTMLElement;
 
   beforeEach(async () => {
     rendererFactory = new RendererFactory();
     document.body.innerHTML =
-      '<div id="storybook-root"></div><div id="root-docs"><div id="story-in-docs"></div></div>';
+      '<div id="storybook-root"></div><div id="root-docs"><div id="story-in-docs"></div></div>' +
+      '<div id="storybook-docs"></div>';
     rootTargetDOMNode = global.document.getElementById('storybook-root');
     rootDocstargetDOMNode = global.document.getElementById('root-docs');
     (platformBrowserDynamic as any).mockImplementation(platformBrowserDynamicTesting);
@@ -180,5 +182,47 @@ describe('RendererFactory', () => {
       const render = await rendererFactory.getRendererInstance(rootDocstargetDOMNode);
       expect(render).toBeInstanceOf(DocsRenderer);
     });
+
+    describe('when multiple story for the same component', () => {
+      it('should render both stories', async () => {
+        @Component({ selector: 'foo', template: '🦊' })
+        class FooComponent {}
+
+        const render = await rendererFactory.getRendererInstance(
+          global.document.getElementById('storybook-docs')
+        );
+
+        const targetDOMNode1 = global.document.createElement('div');
+        targetDOMNode1.id = 'story-1';
+        global.document.getElementById('storybook-docs').appendChild(targetDOMNode1);
+        await render?.render({
+          storyFnAngular: {
+            props: {},
+          },
+          forced: false,
+          component: FooComponent,
+          targetDOMNode: targetDOMNode1,
+        });
+
+        const targetDOMNode2 = global.document.createElement('div');
+        targetDOMNode2.id = 'story-1';
+        global.document.getElementById('storybook-docs').appendChild(targetDOMNode2);
+        await render?.render({
+          storyFnAngular: {
+            props: {},
+          },
+          forced: false,
+          component: FooComponent,
+          targetDOMNode: targetDOMNode2,
+        });
+
+        expect(global.document.querySelectorAll('#story-1 > story-1')[0].innerHTML).toBe(
+          '<foo>🦊</foo><!--container-->'
+        );
+        expect(global.document.querySelectorAll('#story-1 > story-1')[1].innerHTML).toBe(
+          '<foo>🦊</foo><!--container-->'
+        );
+      });
+    });
   });
 });

code/frameworks/angular/src/client/angular-beta/utils/StoryUID.ts

@@ -0,0 +1,43 @@
+/**
+ * Count of stories for each storyId.
+ */
+const storyCounts = new Map<string, number>();
+
+/**
+ * Increments the count for a storyId and returns the next UID.
+ *
+ * When a story is bootstrapped, the storyId is used as the element tag. That
+ * becomes an issue when a story is rendered multiple times in the same docs
+ * page. This function returns a UID that is appended to the storyId to make
+ * it unique.
+ *
+ * @param storyId id of a story
+ * @returns uid of a story
+ */
+export const getNextStoryUID = (storyId: string): string => {
+  if (!storyCounts.has(storyId)) {
+    storyCounts.set(storyId, -1);
+  }
+
+  const count = storyCounts.get(storyId) + 1;
+  storyCounts.set(storyId, count);
+  return `${storyId}-${count}`;
+};
+
+/**
+ * Clears the storyId counts.
+ *
+ * Can be useful for testing, where you need predictable increments, without
+ * reloading the global state.
+ *
+ * If onlyStoryId is provided, only that storyId is cleared.
+ *
+ * @param onlyStoryId id of a story
+ */
+export const clearStoryUIDs = (onlyStoryId?: string): void => {
+  if (onlyStoryId !== undefined && onlyStoryId !== null) {
+    storyCounts.delete(onlyStoryId);
+  } else {
+    storyCounts.clear();
+  }
+};