storybookjs · yannbf · Feb 24, 2026 · Nov 25, 2025 · Nov 26, 2025 · Nov 26, 2025
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,10 @@
+## 10.2.11
+
+- Addon-Vitest: Fix postinstall a11y installation - [#33888](https://github.com/storybookjs/storybook/pull/33888), thanks @valentinpalkovic!
+- Manifests: Use correct story name - [#33709](https://github.com/storybookjs/storybook/pull/33709), thanks @JReinhold!
+- Next.js: Handle legacyBehavior prop in Link mock component  - [#33862](https://github.com/storybookjs/storybook/pull/33862), thanks @yatishgoel!
+- React: Fix manifest stories empty when meta has no explicit title - [#33878](https://github.com/storybookjs/storybook/pull/33878), thanks @kasperpeulen!
+
 ## 10.2.10
 
 - Core: Require token for websocket connections - [#33820](https://github.com/storybookjs/storybook/pull/33820), thanks @ghengeveld!

diff --git a/CHANGELOG.prerelease.md b/CHANGELOG.prerelease.md
@@ -1,3 +1,10 @@
+## 10.3.0-alpha.10
+
+- Addon-Vitest: Fix postinstall a11y installation - [#33888](https://github.com/storybookjs/storybook/pull/33888), thanks @valentinpalkovic!
+- Builder-Vite: Use preview annotations as entry points for optimizeDeps - [#33875](https://github.com/storybookjs/storybook/pull/33875), thanks @copilot-swe-agent!
+- React Native Web: Fix inconsistent example stories - [#33891](https://github.com/storybookjs/storybook/pull/33891), thanks @danielalanbates!
+- Webpack: Improve performance of module-mocking plugins - [#33169](https://github.com/storybookjs/storybook/pull/33169), thanks @valentinpalkovic!
+
 ## 10.3.0-alpha.9
 
 - React: Add react-docgen-typescript to component manifest - [#33818](https://github.com/storybookjs/storybook/pull/33818), thanks @kasperpeulen!

diff --git a/code/addons/docs/src/preset.ts b/code/addons/docs/src/preset.ts
@@ -215,6 +215,9 @@ const optimizeViteDeps = [
   '@storybook/addon-docs',
   '@storybook/addon-docs/blocks',
   '@storybook/addon-docs > @mdx-js/react',
+  '@storybook/addon-docs > @storybook/react-dom-shim',
+  'react-dom/client',
+  'react/jsx-runtime',
 ];
 
 export { webpackX as webpack, docsX as docs, optimizeViteDeps };

diff --git a/code/builders/builder-vite/src/codegen-modern-iframe-script.test.ts b/code/builders/builder-vite/src/codegen-modern-iframe-script.test.ts
@@ -1,6 +1,8 @@
 import { describe, expect, it } from 'vitest';
 
 import { generateModernIframeScriptCodeFromPreviews } from './codegen-modern-iframe-script';
+import { generateAddonSetupCode } from './codegen-set-addon-channel';
+import { optimizeViteDeps } from './preset';
 
 describe('generateModernIframeScriptCodeFromPreviews', () => {
   it('handle one annotation', async () => {
@@ -131,3 +133,60 @@ describe('generateModernIframeScriptCodeFromPreviews', () => {
     `);
   });
 });
+
+/**
+ * Extract bare package import specifiers from a block of generated JavaScript/TypeScript code.
+ * Captures both `import ... from 'pkg'` and `import 'pkg'` forms, excluding:
+ *
+ * - Relative paths (start with `.`)
+ * - Virtual module IDs (start with `virtual:`)
+ * - Absolute paths (start with `/`)
+ */
+function extractPackageImports(code: string): string[] {
+  const importRegex = /import\s+(?:[^'"]*\s+from\s+)?['"]([^'"]+)['"]/g;
+  const specifiers = new Set<string>();
+  for (const match of code.matchAll(importRegex)) {
+    const specifier = match[1];
+    if (
+      !specifier.startsWith('.') &&
+      !specifier.startsWith('virtual:') &&
+      !specifier.startsWith('/')
+    ) {
+      specifiers.add(specifier);
+    }
+  }
+  return [...specifiers];
+}
+
+describe('optimizeDeps coverage for virtual module imports', () => {
+  it('every package imported in virtual module code is either in optimizeViteDeps or known to be discovered via entry crawling', async () => {
+    // Collect all code generated for virtual modules — Vite's dep scanner never sees
+    // the contents of virtual modules, so any package imported there must be
+    // pre-bundled explicitly via optimizeViteDeps.
+    const iframeCode = await generateModernIframeScriptCodeFromPreviews({ frameworkName: 'test' });
+    const addonCode = await generateAddonSetupCode();
+    const allVirtualModuleCode = [iframeCode, addonCode].join('\n');
+
+    const packageImports = extractPackageImports(allVirtualModuleCode);
+
+    // These packages are also imported in real source files (preview annotations, renderer
+    // previews, addon previews) that ARE added as optimizeDeps entries, so Vite discovers
+    // them via entry crawling. No explicit optimizeViteDeps entry is required.
+    const discoveredViaEntries = new Set([
+      'storybook/preview-api', // Imported in many renderer/addon preview files
+      'storybook/internal/channels', // Imported in addon preview files
+    ]);
+
+    const notCovered = packageImports.filter(
+      (pkg) => !discoveredViaEntries.has(pkg) && !optimizeViteDeps.includes(pkg)
+    );
+
+    expect(
+      notCovered,
+      `The following packages are imported in virtual module code but are NOT covered.\n` +
+        `They must be added to optimizeViteDeps in builder-vite/src/preset.ts, OR added to\n` +
+        `the discoveredViaEntries set in this test if they appear in real source entry files.\n` +
+        `Uncovered: ${notCovered.join(', ')}`
+    ).toHaveLength(0);
+  });
+});
diff --git a/code/builders/builder-vite/src/constants.ts b/code/builders/builder-vite/src/constants.ts
diff --git a/code/builders/builder-vite/src/optimizeDeps.ts b/code/builders/builder-vite/src/optimizeDeps.ts
diff --git a/code/builders/builder-vite/src/plugins/storybook-optimize-deps-plugin.ts b/code/builders/builder-vite/src/plugins/storybook-optimize-deps-plugin.ts
@@ -1,8 +1,11 @@
+import { loadPreviewOrConfigFile } from 'storybook/internal/common';
 import type { StoryIndexGenerator } from 'storybook/internal/core-server';
-import type { Options, StoryIndex } from 'storybook/internal/types';
+import type { Options, PreviewAnnotation, StoryIndex } from 'storybook/internal/types';
 
+import { resolve } from 'pathe';
 import { type Plugin } from 'vite';
 
+import { processPreviewAnnotation } from '../utils/process-preview-annotation';
 import { getUniqueImportPaths } from '../utils/unique-import-paths';
 
 /** A Vite plugin that configures dependency optimization for Storybook's dev server. */
@@ -15,25 +18,37 @@ export function storybookOptimizeDepsPlugin(options: Options): Plugin {
         return;
       }
 
-      const [extraOptimizeDeps, storyIndexGenerator] = await Promise.all([
-        options.presets.apply('optimizeViteDeps', []),
+      const projectRoot = resolve(options.configDir, '..');
+
+      const [extraOptimizeDeps, storyIndexGenerator, previewAnnotations] = await Promise.all([
+        options.presets.apply<string[]>('optimizeViteDeps', []),
         options.presets.apply<StoryIndexGenerator>('storyIndexGenerator'),
+        options.presets.apply<PreviewAnnotation[]>('previewAnnotations', [], options),
       ]);
 
       const index: StoryIndex = await storyIndexGenerator.getIndex();
 
+      // Include the user's preview file and all addon/framework/renderer preview annotations
+      // as optimizer entries so Vite can discover all transitive CJS dependencies automatically.
+      const previewOrConfigFile = loadPreviewOrConfigFile({ configDir: options.configDir });
+      const previewAnnotationEntries = [...previewAnnotations, previewOrConfigFile]
+        .filter((path): path is PreviewAnnotation => path !== undefined)
+        .map((path) => processPreviewAnnotation(path, projectRoot));
+
       return {
         optimizeDeps: {
-          // Story file paths as entry points for the optimizer
+          // Story files + preview annotation files as entry points for the dep optimizer.
+          // Vite will crawl these to discover all transitive CJS dependencies that need
+          // pre-bundling, removing the need for a hard-coded include list.
           entries: [
             ...(typeof config.optimizeDeps?.entries === 'string'
               ? [config.optimizeDeps.entries]
-              : []),
+              : (config.optimizeDeps?.entries ?? [])),
             ...getUniqueImportPaths(index),
+            ...previewAnnotationEntries,
           ],
-          // Known CJS dependencies that need to be pre-compiled to ESM,
-          // plus any extra deps from Storybook presets.
-          include: [...extraOptimizeDeps, ...(config.optimizeDeps?.include || [])],
+          // Extra deps explicitly included by Storybook presets (e.g. framework-specific packages).
+          include: [...extraOptimizeDeps, ...(config.optimizeDeps?.include ?? [])],
         },
       };
     },

diff --git a/code/builders/builder-vite/src/preset.ts b/code/builders/builder-vite/src/preset.ts
@@ -10,6 +10,8 @@ import { storybookSanitizeEnvs } from './plugins/storybook-runtime-plugin';
 import { viteInjectMockerRuntime } from './plugins/vite-inject-mocker/plugin';
 import { viteMockPlugin } from './plugins/vite-mock/plugin';
 
+export const optimizeViteDeps: string[] = ['storybook/internal/preview/runtime'];
+
 /**
  * Preset that provides the core Storybook Vite plugins shared between `@storybook/builder-vite` and
  * `@storybook/addon-vitest`.

diff --git a/code/builders/builder-vite/src/vite-server.ts b/code/builders/builder-vite/src/vite-server.ts
@@ -6,23 +6,15 @@ import { dedent } from 'ts-dedent';
 import type { InlineConfig, ServerOptions } from 'vite';
 
 import { createViteLogger } from './logger';
-import { getOptimizeDeps } from './optimizeDeps';
 import { commonConfig } from './vite-config';
 
 export async function createViteServer(options: Options, devServer: Server) {
   const { presets } = options;
 
   const commonCfg = await commonConfig(options, 'development');
 
-  const optimizeDeps = await getOptimizeDeps(commonCfg);
-
   const config: InlineConfig & { server: ServerOptions } = {
     ...commonCfg,
-    // Set up dev server
-    optimizeDeps: {
-      ...commonCfg.optimizeDeps,
-      include: [...(commonCfg.optimizeDeps?.include || []), ...optimizeDeps.include],
-    },
     server: {
       middlewareMode: true,
       hmr: {

diff --git a/code/builders/builder-webpack5/src/plugins/webpack-inject-mocker-runtime-plugin.ts b/code/builders/builder-webpack5/src/plugins/webpack-inject-mocker-runtime-plugin.ts
@@ -13,6 +13,7 @@ const PLUGIN_NAME = 'WebpackInjectMockerRuntimePlugin';
  * Storybook preview bundle, are executed.
  */
 export class WebpackInjectMockerRuntimePlugin {
+  private cachedRuntime: string | null = null;
   // We need to lazy-require HtmlWebpackPlugin because it's an optional peer dependency.
   private getHtmlWebpackPlugin(compiler: Compiler): typeof HtmlWebpackPlugin | null {
     try {
@@ -52,20 +53,23 @@ export class WebpackInjectMockerRuntimePlugin {
         PLUGIN_NAME,
         (data, cb) => {
           try {
-            const runtimeScriptContent = getMockerRuntime();
+            const runtimeScriptContent =
+              this.cachedRuntime ?? (this.cachedRuntime = getMockerRuntime());
             const runtimeAssetName = 'mocker-runtime-injected.js';
 
             // Use the documented `emitAsset` method to add the pre-bundled runtime script
             // to the compilation's assets. This is the standard Webpack way.
-            compilation.emitAsset(
-              runtimeAssetName,
-              new compiler.webpack.sources.RawSource(runtimeScriptContent)
-            );
+            if (!compilation.getAsset(runtimeAssetName)) {
+              compilation.emitAsset(
+                runtimeAssetName,
+                new compiler.webpack.sources.RawSource(runtimeScriptContent)
+              );
+              data.assets.js.unshift(runtimeAssetName);
+            }
 
-            // Prepend the name of our new asset to the list of JavaScript files.
+            // Prepend the name of our new asset to the list of JavaScript files, once.
             // HtmlWebpackPlugin will automatically create a <script> tag for it
             // and place it at the beginning of the body scripts.
-            data.assets.js.unshift(runtimeAssetName);
             cb(null, data);
           } catch (error) {
             // In case of an error (e.g., file not found), pass it to Webpack's compilation.