Add deprecation note + pass through loadStory

MIGRATION.md

@@ -63,7 +63,7 @@
     - [Canvas Doc block properties](#canvas-doc-block-properties)
     - [`Primary` Doc block properties](#primary-doc-block-properties)
     - [`createChannel` from `@storybook/postmessage` and  `@storybook/channel-websocket`](#createchannel-from-storybookpostmessage-and--storybookchannel-websocket)
-    - [StoryStore methods deprecated](#storystore-methods-deprecated)
+    - [StoryStore and methods deprecated](#storystore-and-methods-deprecated)
 - [From version 7.5.0 to 7.6.0](#from-version-750-to-760)
     - [CommonJS with Vite is deprecated](#commonjs-with-vite-is-deprecated)
     - [Using implicit actions during rendering is deprecated](#using-implicit-actions-during-rendering-is-deprecated)
@@ -978,11 +978,17 @@ The `name` prop is now removed in favor of the `of` property. [More info](#doc-b
 The `createChannel` APIs from both `@storybook/channel-websocket` and `@storybook/postmessage` are now removed. Please use `createBrowserChannel` instead, from the `@storybook/channels` package.
 
 Additionally, the `PostmsgTransport` type is now removed in favor of `PostMessageTransport`.
-#### StoryStore methods deprecated
 
-The following methods on the `StoryStore` are deprecated and will be removed in 9.0:
-  - `store.fromId()` - please use `store.loadStory()` instead.
-  - `store.raw()` - please use `store.extract()` instead.
+
+#### StoryStore and methods deprecated
+
+The StoryStore (`__STORYBOOK_STORY_STORE__` and `__STORYBOOK_PREVIEW__.storyStore`) are deprecated, and will no longer be accessible in Storybook 9.0.
+
+In particular, the following methods on the `StoryStore` are deprecated and will be removed in 9.0:
+  - `store.fromId()` - please use `preview.loadStory({ storyId })` instead.
+  - `store.raw()` - please use `preview.extract()` instead.
+
+Note that both these methods require initialization, so you should await `preview.ready()`.
 
 ## From version 7.5.0 to 7.6.0
 

code/lib/preview-api/src/modules/preview-web/Preview.tsx

@@ -377,6 +377,13 @@ export class Preview<TRenderer extends Renderer> {
   }
 
   // API
+  async loadStory({ storyId }: { storyId: StoryId }) {
+    if (!this.storyStoreValue)
+      throw new CalledPreviewMethodBeforeInitializationError({ methodName: 'loadStory' });
+
+    return this.storyStoreValue.loadStory({ storyId });
+  }
+
   async extract(options?: { includeDocsOnly: boolean }) {
     if (!this.storyStoreValue)
       throw new CalledPreviewMethodBeforeInitializationError({ methodName: 'extract' });