Blocks: Add of prop to Title

MIGRATION.md

@@ -2,6 +2,7 @@
 
 - [From version 8.0 to 8.1.0](#from-version-80-to-810)
   - [Subtitle block and `parameters.componentSubtitle`](#subtitle-block-and-parameterscomponentsubtitle)
+      - [Title block](#title-block)
 - [From version 7.x to 8.0.0](#from-version-7x-to-800)
   - [Portable stories](#portable-stories)
     - [Project annotations are now merged instead of overwritten in composeStory](#project-annotations-are-now-merged-instead-of-overwritten-in-composestory)
@@ -413,6 +414,12 @@ The `Subtitle` block now accepts an `of` prop, which can be a reference to a CSF
 
 `parameters.componentSubtitle` has been deprecated to be consistent with other parameters related to autodocs, instead use `parameters.docs.subtitle`.
 
+##### Title block
+
+The `Title` block now accepts an `of` prop, which can be a reference to a CSF file or a default export (meta).
+
+It still accepts being passed `children`.
+
 ## From version 7.x to 8.0.0
 
 ### Portable stories

code/ui/blocks/src/blocks/Title.stories.tsx

@@ -0,0 +1,55 @@
+import type { Meta, StoryObj } from '@storybook/react';
+import { Title } from './Title';
+import * as DefaultButtonStories from '../examples/Button.stories';
+
+const meta: Meta<typeof Title> = {
+  component: Title,
+  title: 'Blocks/Title',
+  parameters: {
+    controls: {
+      include: [],
+      hideNoControlsWarning: true,
+    },
+    // workaround for https://github.com/storybookjs/storybook/issues/20505
+    docs: { source: { type: 'code' } },
+    attached: false,
+    docsStyles: true,
+  },
+};
+export default meta;
+
+type Story = StoryObj<typeof meta>;
+
+export const OfCSFFile: Story = {
+  args: {
+    of: DefaultButtonStories,
+  },
+  parameters: { relativeCsfPaths: ['../examples/Button.stories'] },
+};
+
+export const OfMeta: Story = {
+  args: {
+    of: DefaultButtonStories,
+  },
+  parameters: { relativeCsfPaths: ['../examples/Button.stories'] },
+};
+
+export const OfStringMetaAttached: Story = {
+  name: 'Of attached "meta"',
+  args: {
+    of: 'meta',
+  },
+  parameters: { relativeCsfPaths: ['../examples/Button.stories'], attached: true },
+};
+
+export const Children: Story = {
+  args: {
+    children: 'Title as children',
+  },
+  parameters: { relativeCsfPaths: ['../examples/Button.stories'], attached: false },
+};
+
+export const DefaultAttached: Story = {
+  args: {},
+  parameters: { relativeCsfPaths: ['../examples/Button.stories'], attached: true },
+};

code/ui/blocks/src/blocks/Title.tsx

@@ -1,23 +1,48 @@
 import type { ComponentTitle } from '@storybook/types';
 import type { FunctionComponent, ReactNode } from 'react';
-import React, { useContext } from 'react';
+import React from 'react';
 import { Title as PureTitle } from '../components';
-import { DocsContext } from './DocsContext';
+import type { Of } from './useOf';
+import { useOf } from './useOf';
 
 interface TitleProps {
+  /**
+   * Specify where to get the title from. Must be a CSF file's default export.
+   * If not specified, the title will be read from children, or extracted from the meta of the attached CSF file.
+   */
+  of?: Of;
+
+  /**
+   * Specify content to display as the title.
+   */
   children?: ReactNode;
 }
 
 const STORY_KIND_PATH_SEPARATOR = /\s*\/\s*/;
 
 export const extractTitle = (title: ComponentTitle) => {
   const groups = title.trim().split(STORY_KIND_PATH_SEPARATOR);
-  return (groups && groups[groups.length - 1]) || title;
+  return groups?.[groups?.length - 1] || title;
 };
 
-export const Title: FunctionComponent<TitleProps> = ({ children }) => {
-  const context = useContext(DocsContext);
-  const content = children || extractTitle(context.storyById().title);
+export const Title: FunctionComponent<TitleProps> = (props) => {
+  const { children, of } = props;
+
+  if ('of' in props && of === undefined) {
+    throw new Error('Unexpected `of={undefined}`, did you mistype a CSF file reference?');
+  }
+
+  let preparedMeta;
+  try {
+    preparedMeta = useOf(of || 'meta', ['meta']).preparedMeta;
+  } catch (error) {
+    if (children && !error.message.includes('did you forget to use <Meta of={} />?')) {
+      // ignore error about unattached CSF since we can still render children
+      throw error;
+    }
+  }
+
+  const content = children || extractTitle(preparedMeta.title);
 
   return content ? <PureTitle className="sbdocs-title sb-unstyled">{content}</PureTitle> : null;
 };

docs/api/doc-block-title.md

@@ -31,3 +31,9 @@ import { Title } from '@storybook/blocks';
 Type: `JSX.Element | string`
 
 Provides the content. Falls back to value of `title` in an [attached](./doc-block-meta.md#attached-vs-unattached) CSF file (or value derived from [autotitle](../configure/sidebar-and-urls.md#csf-30-auto-titles)), trimmed to the last segment. For example, if the title value is `'path/to/components/Button'`, the default content is `'Button'`.
+
+### `of`
+
+Type: CSF file exports
+
+Specifies which meta's title is displayed.