Core: Replace lodash with es-toolkit

code/core/package.json

@@ -321,7 +321,6 @@
     "@types/find-cache-dir": "^5.0.0",
     "@types/fs-extra": "^11.0.1",
     "@types/js-yaml": "^4.0.5",
-    "@types/lodash": "^4.14.167",
     "@types/node": "^22.0.0",
     "@types/npmlog": "^7.0.0",
     "@types/picomatch": "^2.3.0",
@@ -360,6 +359,7 @@
     "diff": "^5.2.0",
     "downshift": "^9.0.4",
     "ejs": "^3.1.10",
+    "es-toolkit": "^1.16.0",
     "esbuild": "^0.18.0 || ^0.19.0 || ^0.20.0 || ^0.21.0 || ^0.22.0 || ^0.23.0",
     "esbuild-plugin-alias": "^0.2.1",
     "execa": "^8.0.1",
@@ -380,7 +380,6 @@
     "jsdoc-type-pratt-parser": "^4.0.0",
     "lazy-universal-dotenv": "^4.0.0",
     "leven": "^4.0.0",
-    "lodash": "^4.17.21",
     "markdown-to-jsx": "^7.4.5",
     "memfs": "^4.11.1",
     "memoizerific": "^1.11.3",

code/core/src/common/js-package-manager/JsPackageManager.ts

@@ -60,7 +60,7 @@ export abstract class JsPackageManager {
   /** Get the INSTALLED version of a package from the package.json file */
   async getPackageVersion(packageName: string, basePath = this.cwd): Promise<string | null> {
     const packageJSON = await this.getPackageJSON(packageName, basePath);
-    return packageJSON ? packageJSON.version ?? null : null;
+    return packageJSON ? (packageJSON.version ?? null) : null;
   }
 
   constructor(options?: JsPackageManagerOptions) {

code/core/src/core-server/utils/stories-json.test.ts

@@ -6,8 +6,8 @@
 
 import { STORY_INDEX_INVALIDATED } from '@storybook/core/core-events';
 
+import { debounce } from 'es-toolkit';
 import type { Request, Response, Router } from 'express';
-import debounce from 'lodash/debounce.js';
 import Watchpack from 'watchpack';
 
 import { csfIndexer } from '../presets/common-preset';
@@ -17,7 +17,7 @@
 import { DEBOUNCE, useStoriesJson } from './stories-json';
 
 vi.mock('watchpack');
-vi.mock('lodash/debounce');
+vi.mock('es-toolkit');
 vi.mock('@storybook/core/node-logger');
 
 const workingDir = join(__dirname, '__mockdata__');
@@ -471,8 +471,7 @@
 
     it('debounces invalidation events', async () => {
       vi.mocked(debounce).mockImplementation(
-        // @ts-expect-error it doesn't think default exists
-        (await vi.importActual<typeof import('lodash/debounce.js')>('lodash/debounce.js')).default
+        (await vi.importActual<typeof import('es-toolkit')>('es-toolkit')).debounce
       );
 
       const mockServerChannel = { emit: vi.fn() } as any as ServerChannel;
@@ -509,7 +508,7 @@
       await onChange(`${workingDir}/src/nested/Button.stories.ts`);
       await onChange(`${workingDir}/src/nested/Button.stories.ts`);
 
       expect(mockServerChannel.emit).toHaveBeenCalledTimes(1);
       expect(mockServerChannel.emit).toHaveBeenCalledWith(STORY_INDEX_INVALIDATED);
 
       await new Promise((r) => setTimeout(r, 2 * DEBOUNCE));

code/core/src/core-server/utils/stories-json.ts

@@ -4,9 +4,9 @@ import type { NormalizedStoriesSpecifier, StoryIndex } from '@storybook/core/typ
 
 import { STORY_INDEX_INVALIDATED } from '@storybook/core/core-events';
 
+import { debounce } from 'es-toolkit';
 import type { Request, Response, Router } from 'express';
 import { writeJSON } from 'fs-extra';
-import debounce from 'lodash/debounce.js';
 
 import type { StoryIndexGenerator } from './StoryIndexGenerator';
 import type { ServerChannel } from './get-server-channel';
@@ -40,9 +40,7 @@ export function useStoriesJson({
   configDir?: string;
   normalizedStories: NormalizedStoriesSpecifier[];
 }) {
-  const maybeInvalidate = debounce(() => serverChannel.emit(STORY_INDEX_INVALIDATED), DEBOUNCE, {
-    leading: true,
-  });
+  const maybeInvalidate = debounce(() => serverChannel.emit(STORY_INDEX_INVALIDATED), DEBOUNCE, {});
   watchStorySpecifiers(normalizedStories, { workingDir }, async (specifier, path, removed) => {
     const generator = await initializedStoryIndexGenerator;
     generator.invalidate(specifier, path, removed);

code/core/src/docs-tools/argTypes/convert/convert.test.ts

@@ -4,7 +4,7 @@ import { describe, expect, it } from 'vitest';
 
 import { transformSync } from '@storybook/core/babel';
 
-import mapValues from 'lodash/mapValues.js';
+import { mapValues } from 'es-toolkit';
 import requireFromString from 'require-from-string';
 
 import { normalizeNewlines } from '../utils';

code/core/src/docs-tools/argTypes/convert/proptypes/convert.ts

@@ -1,6 +1,6 @@
 import type { SBType } from '@storybook/core/types';
 
-import mapValues from 'lodash/mapValues.js';
+import { mapValues } from 'es-toolkit';
 
 import { parseLiteral } from '../utils';
 import type { PTType } from './types';

code/core/src/manager-api/lib/merge.ts

@@ -1,10 +1,13 @@
 import { logger } from '@storybook/core/client-logger';
 
-import isEqual from 'lodash/isEqual.js';
-import mergeWith from 'lodash/mergeWith.js';
+import { isEqual, mergeWith, omitBy, pick } from 'es-toolkit';
 
-export default <TObj = any>(a: TObj, b: Partial<TObj>) =>
-  mergeWith({}, a, b, (objValue: TObj, srcValue: Partial<TObj>) => {
+export default <TObj = any>(a: TObj, ...b: Partial<TObj>[]): TObj => {
+  // start with empty object
+  let target = {};
+
+  // merge object a unto target
+  target = mergeWith({}, a, (objValue: TObj, srcValue: Partial<TObj>) => {
     if (Array.isArray(srcValue) && Array.isArray(objValue)) {
       srcValue.forEach((s) => {
         const existing = objValue.find((o) => o === s || isEqual(o, s));
@@ -19,5 +22,59 @@ export default <TObj = any>(a: TObj, b: Partial<TObj>) =>
       logger.log(['the types mismatch, picking', objValue]);
       return objValue;
     }
-    return undefined;
   });
+
+  for (const obj of b) {
+    // merge object b unto target
+    target = mergeWith(target, obj, (objValue: TObj, srcValue: Partial<TObj>) => {
+      if (Array.isArray(srcValue) && Array.isArray(objValue)) {
+        srcValue.forEach((s) => {
+          const existing = objValue.find((o) => o === s || isEqual(o, s));
+          if (!existing) {
+            objValue.push(s);
+          }
+        });
+
+        return objValue;
+      }
+      if (Array.isArray(objValue)) {
+        logger.log(['the types mismatch, picking', objValue]);
+        return objValue;
+      }
+    });
+  }
+
+  return target as TObj;
+};
+
+export const noArrayMerge = <TObj = any>(a: TObj, ...b: Partial<TObj>[]): TObj => {
+  // start with empty object
+  let target = {};
+
+  // merge object a unto target
+  target = mergeWith({}, a, (objValue: TObj, srcValue: Partial<TObj>) => {
+    // Treat arrays as scalars:
+    if (Array.isArray(srcValue)) {
+      return srcValue;
+    }
+  });
+
+  for (const obj of b) {
+    // merge object b unto target
+    target = mergeWith(target, obj, (objValue: TObj, srcValue: Partial<TObj>) => {
+      // Treat arrays as scalars:
+      if (Array.isArray(srcValue)) {
+        return srcValue;
+      }
+    });
+  }
+
+  return target as TObj;
+};
+
+export function picky<T extends Record<string, any>, K extends keyof T>(
+  obj: T,
+  keys: K[]
+): Partial<Pick<T, K>> {
+  return omitBy(pick(obj, keys), (v) => v === undefined);
+}

code/core/src/manager-api/lib/stories.ts

@@ -19,8 +19,7 @@ import type {
 } from '@storybook/core/types';
 import { sanitize } from '@storybook/csf';
 
-import countBy from 'lodash/countBy.js';
-import mapValues from 'lodash/mapValues.js';
+import { countBy, mapValues } from 'es-toolkit';
 import memoize from 'memoizerific';
 import { dedent } from 'ts-dedent';
 
@@ -41,7 +40,7 @@ export const denormalizeStoryParameters = ({
       kindParameters[storyData.kind],
       storyData.parameters as unknown as Parameters
     ),
-  }));
+  })) as SetStoriesStoryData;
 };
 
 export const transformSetStoriesStoryDataToStoriesHash = (
@@ -112,7 +111,7 @@ export const transformStoryIndexV2toV3 = (index: StoryIndexV2): StoryIndexV3 =>
 };
 
 export const transformStoryIndexV3toV4 = (index: StoryIndexV3): API_PreparedStoryIndex => {
-  const countByTitle = countBy(Object.values(index.stories), 'title');
+  const countByTitle = countBy(Object.values(index.stories), (item) => item.title);
   return {
     v: 4,
     entries: Object.values(index.stories).reduce(

code/core/src/manager-api/modules/layout.ts

@@ -5,10 +5,9 @@ import { global } from '@storybook/global';
 
 import { SET_CONFIG } from '@storybook/core/core-events';
 
-import { dequal as deepEqual } from 'dequal';
-import pick from 'lodash/pick.js';
+import { isEqual as deepEqual, omitBy, pick, toMerged } from 'es-toolkit';
 
-import merge from '../lib/merge';
+import merge, { picky } from '../lib/merge';
 import type { ModuleFn } from '../lib/types';
 import type { State } from '../root';
 
@@ -320,12 +319,15 @@ export const init: ModuleFn<SubAPI, SubState> = ({ store, provider, singleStory
         ...defaultLayoutState,
         layout: {
           ...defaultLayoutState.layout,
-          ...pick(options, Object.keys(defaultLayoutState.layout)),
+          ...toMerged(
+            defaultLayoutState.layout,
+            pick(options, Object.keys(defaultLayoutState.layout))
+          ),
           ...(singleStory && { navSize: 0 }),
         },
         ui: {
           ...defaultLayoutState.ui,
-          ...pick(options, Object.keys(defaultLayoutState.ui)),
+          ...toMerged(defaultLayoutState.ui, pick(options, Object.keys(defaultLayoutState.ui))),
         },
         selectedPanel: selectedPanel || defaultLayoutState.selectedPanel,
         theme: theme || defaultLayoutState.theme,
@@ -351,15 +353,15 @@ export const init: ModuleFn<SubAPI, SubState> = ({ store, provider, singleStory
 
       const updatedLayout = {
         ...layout,
-        ...options.layout,
-        ...pick(options, Object.keys(layout)),
+        ...(options.layout || {}),
+        ...picky(options, Object.keys(layout)),
         ...(singleStory && { navSize: 0 }),
       };
 
       const updatedUi = {
         ...ui,
         ...options.ui,
-        ...pick(options, Object.keys(ui)),
+        ...toMerged(options.ui || {}, picky(options, Object.keys(ui))),
       };
 
       const updatedTheme = {
@@ -388,7 +390,7 @@ export const init: ModuleFn<SubAPI, SubState> = ({ store, provider, singleStory
     },
   };
 
-  const persisted = pick(store.getState(), 'layout', 'selectedPanel');
+  const persisted = pick(store.getState(), ['layout', 'selectedPanel']);
 
   provider.channel?.on(SET_CONFIG, () => {
     api.setOptions(merge(api.getInitialOptions(), persisted));

code/core/src/manager-api/modules/notifications.ts

@@ -1,6 +1,6 @@
 import type { API_Notification } from '@storybook/core/types';
 
-import partition from 'lodash/partition.js';
+import { partition } from 'es-toolkit';
 
 import type { ModuleFn } from '../lib/types';
 

code/core/src/manager-api/root.tsx

@@ -41,11 +41,12 @@ import {
   STORY_CHANGED,
 } from '@storybook/core/core-events';
 
-import mergeWith from 'lodash/mergeWith.js';
+import { mergeWith } from 'es-toolkit';
 
 import { createContext } from './context';
 import getInitialState from './initial-state';
 import { types } from './lib/addons';
+import { noArrayMerge } from './lib/merge';
 import type { ModuleFn } from './lib/types';
 import * as addons from './modules/addons';
 import * as channel from './modules/channel';
@@ -129,14 +130,7 @@ export type ManagerProviderProps = RouterData &
 
 // This is duplicated from @storybook/preview-api for the reasons mentioned in lib-addons/types.js
 export const combineParameters = (...parameterSets: Parameters[]) =>
-  mergeWith({}, ...parameterSets, (objValue: any, srcValue: any) => {
-    // Treat arrays as scalars:
-    if (Array.isArray(srcValue)) {
-      return srcValue;
-    }
-
-    return undefined;
-  });
+  noArrayMerge({}, ...parameterSets);
 
 class ManagerProvider extends Component<ManagerProviderProps, State> {
   api: API = {} as API;

code/core/src/manager/components/mobile/navigation/MobileNavigation.stories.tsx

@@ -5,7 +5,7 @@ import { within } from '@storybook/test';
 
 import { ManagerContext } from '@storybook/core/manager-api';
 
-import { startCase } from 'lodash';
+import { startCase } from 'es-toolkit';
 
 import { LayoutProvider, useLayout } from '../../layout/LayoutProvider';
 import { MobileNavigation } from './MobileNavigation';

code/core/src/manager/components/preview/Preview.tsx

@@ -202,7 +202,7 @@ export function filterTabs(panels: Addon_BaseType[], parameters?: Record<string,
 
   if (previewTabs || parametersTabs) {
     // deep merge global and local settings
-    const tabs = merge(previewTabs, parametersTabs);
+    const tabs = merge(previewTabs || {}, parametersTabs || {});
     const arrTabs = Object.keys(tabs).map((key, index) => ({
       index,
       ...(typeof tabs[key] === 'string' ? { title: tabs[key] } : tabs[key]),

code/core/src/manager/components/preview/Toolbar.tsx

@@ -188,7 +188,10 @@ function toolbarItemHasBeenExcluded(item: Partial<Addon_BaseType>, entry: LeafEn
   const toolbarItemsFromStoryParameters = 'toolbar' in parameters ? parameters.toolbar : undefined;
   const { toolbar: toolbarItemsFromAddonsConfig } = addons.getConfig();
 
-  const toolbarItems = merge(toolbarItemsFromAddonsConfig, toolbarItemsFromStoryParameters);
+  const toolbarItems = merge(
+    toolbarItemsFromAddonsConfig || {},
+    toolbarItemsFromStoryParameters || {}
+  );
 
   // @ts-expect-error (non strict)
   return toolbarItems ? !!toolbarItems[item?.id]?.hidden : false;

code/core/src/manager/components/sidebar/useExpanded.ts

@@ -7,7 +7,7 @@ import { STORIES_COLLAPSE_ALL, STORIES_EXPAND_ALL } from '@storybook/core/core-e
 import type { StoriesHash } from '@storybook/core/manager-api';
 import { useStorybookApi } from '@storybook/core/manager-api';
 
-import throttle from 'lodash/throttle.js';
+import { throttle } from 'es-toolkit';
 
 import { matchesKeyCode, matchesModifiers } from '../../keybinding';
 import { getAncestorIds, getDescendantIds, isAncestor, scrollIntoView } from '../../utils/tree';

code/core/src/manager/components/sidebar/useLastViewed.ts

@@ -1,6 +1,6 @@
 import { useCallback, useEffect, useMemo, useRef } from 'react';
 
-import debounce from 'lodash/debounce.js';
+import { debounce } from 'es-toolkit';
 import store from 'store2';
 
 import type { Selection, StoryRef } from './types';

code/core/src/preview-api/modules/preview-web/PreviewWeb.test.ts

@@ -31,7 +31,7 @@ import {
   UPDATE_STORY_ARGS,
 } from '@storybook/core/core-events';
 
-import merge from 'lodash/merge.js';
+import { merge, toMerged } from 'es-toolkit';
 
 import { addons } from '../addons';
 import type { StoryStore } from '../store';
@@ -308,7 +308,7 @@ describe('PreviewWeb', () => {
         expect(mockChannel.emit).toHaveBeenCalledWith(STORY_MISSING, 'component-one--missing');
 
         mockChannel.emit.mockClear();
-        const newComponentOneExports = merge({}, componentOneExports, {
+        const newComponentOneExports = toMerged(componentOneExports, {
           d: { args: { foo: 'd' }, play: vi.fn() },
         });
         const newImportFn = vi.fn(async (path) => {
@@ -362,7 +362,7 @@ describe('PreviewWeb', () => {
           });
           await waitForSetCurrentStory();
 
-          const newComponentOneExports = merge({}, componentOneExports, {
+          const newComponentOneExports = toMerged(componentOneExports, {
             d: { args: { foo: 'd' }, play: vi.fn() },
           });
           const newImportFn = vi.fn(async (path) => {
@@ -2927,7 +2927,7 @@ describe('PreviewWeb', () => {
     });
 
     describe('when the current story changes', () => {
-      const newComponentOneExports = merge({}, componentOneExports, {
+      const newComponentOneExports = toMerged(componentOneExports, {
         a: { args: { foo: 'edited' } },
       });
       const newImportFn = vi.fn(async (path) => {
@@ -3282,7 +3282,7 @@ describe('PreviewWeb', () => {
       afterEach(() => {
         vi.useRealTimers();
       });
-      const newComponentOneExports = merge({}, componentOneExports, {
+      const newComponentOneExports = toMerged(componentOneExports, {
         a: { args: { bar: 'edited' }, argTypes: { bar: { type: { name: 'string' } } } },
       });
       const newImportFn = vi.fn(async (path) => {