refactor: replace unifiedFontStore with fontStore in comparisonStore tests

.gitignore

@@ -10,6 +10,9 @@ node_modules
 /build
 /dist
 
+# Git worktrees (isolated development branches)
+.worktrees
+
 # OS
 .DS_Store
 Thumbs.db

src/entities/Font/index.ts

@@ -1,115 +1,3 @@
-// Proxy API (primary)
-export {
-    fetchFontsByIds,
-    fetchProxyFontById,
-    fetchProxyFonts,
-} from './api/proxy/proxyFonts';
-export type {
-    ProxyFontsParams,
-    ProxyFontsResponse,
-} from './api/proxy/proxyFonts';
-
-export {
-    normalizeFontshareFont,
-    normalizeFontshareFonts,
-} from './lib/normalize/normalize';
-export type {
-    // Domain types
-    FontCategory,
-    FontCollectionFilters,
-    FontCollectionSort,
-    // Store types
-    FontCollectionState,
-    FontFeatures,
-    FontFiles,
-    FontItem,
-    FontMetadata,
-    FontProvider,
-    // Fontshare API types
-    FontshareApiModel,
-    FontshareAxis,
-    FontshareDesigner,
-    FontshareFeature,
-    FontshareFont,
-    FontshareLink,
-    FontsharePublisher,
-    FontshareStyle,
-    FontshareStyleProperties,
-    FontshareTag,
-    FontshareWeight,
-    FontStyleUrls,
-    FontSubset,
-    FontVariant,
-    FontWeight,
-    FontWeightItalic,
-    // Normalization types
-    UnifiedFont,
-    UnifiedFontVariant,
-} from './model';
-
-export {
-    appliedFontsManager,
-    createUnifiedFontStore,
-    unifiedFontStore,
-} from './model';
-
-// Mock data helpers for Storybook and testing
-export {
-    createCategoriesFilter,
-    createErrorState,
-    createGenericFilter,
-    createLoadingState,
-    createMockComparisonStore,
-    // Filter mocks
-    createMockFilter,
-    createMockFontApiResponse,
-    createMockFontStoreState,
-    // Store mocks
-    createMockQueryState,
-    createMockReactiveState,
-    createMockStore,
-    createProvidersFilter,
-    createSubsetsFilter,
-    createSuccessState,
-    FONTHARE_FONTS,
-    generateMixedCategoryFonts,
-    generateMockFonts,
-    generatePaginatedFonts,
-    generateSequentialFilter,
-    GENERIC_FILTERS,
-    getAllMockFonts,
-    getFontsByCategory,
-    getFontsByProvider,
-    GOOGLE_FONTS,
-    MOCK_FILTERS,
-    MOCK_FILTERS_ALL_SELECTED,
-    MOCK_FILTERS_EMPTY,
-    MOCK_FILTERS_SELECTED,
-    MOCK_FONT_STORE_STATES,
-    MOCK_STORES,
-    type MockFilterOptions,
-    type MockFilters,
-    mockFontshareFont,
-    type MockFontshareFontOptions,
-    type MockFontStoreState,
-    // Font mocks
-    mockGoogleFont,
-    // Types
-    type MockGoogleFontOptions,
-    type MockQueryObserverResult,
-    type MockQueryState,
-    mockUnifiedFont,
-    type MockUnifiedFontOptions,
-    UNIFIED_FONTS,
-} from './lib/mocks';
-
-export {
-    FontNetworkError,
-    FontResponseError,
-} from './lib/errors/errors';
-
-// UI elements
-export {
-    FontApplicator,
-    FontVirtualList,
-} from './ui';
+export * from './api';
+export * from './model';
+export * from './ui';

src/entities/Font/lib/mocks/stores.mock.ts

@@ -20,7 +20,7 @@
  * const successState = createMockQueryState({ status: 'success', data: mockFonts });
  *
  * // Use preset stores
- * const mockFontStore = MOCK_STORES.unifiedFontStore();
+ * const mockFontStore = createMockFontStore();
  * ```
  */
 
@@ -459,6 +459,117 @@ export const MOCK_STORES = {
             resetFilters: () => {},
         };
     },
+    /**
+     * Create a mock FontStore object
+     * Matches FontStore's public API for Storybook use
+     */
+    fontStore: (config: {
+        fonts?: UnifiedFont[];
+        total?: number;
+        limit?: number;
+        offset?: number;
+        isLoading?: boolean;
+        isFetching?: boolean;
+        isError?: boolean;
+        error?: Error | null;
+        hasMore?: boolean;
+        page?: number;
+    } = {}) => {
+        const {
+            fonts: mockFonts = Object.values(UNIFIED_FONTS).slice(0, 5),
+            total: mockTotal = mockFonts.length,
+            limit = 50,
+            offset = 0,
+            isLoading = false,
+            isFetching = false,
+            isError = false,
+            error = null,
+            hasMore = false,
+            page = 1,
+        } = config;
+
+        const totalPages = Math.ceil(mockTotal / limit);
+        const state = {
+            params: { limit },
+        };
+
+        return {
+            // State getters
+            get params() {
+                return state.params;
+            },
+            get fonts() {
+                return mockFonts;
+            },
+            get isLoading() {
+                return isLoading;
+            },
+            get isFetching() {
+                return isFetching;
+            },
+            get isError() {
+                return isError;
+            },
+            get error() {
+                return error;
+            },
+            get isEmpty() {
+                return !isLoading && !isFetching && mockFonts.length === 0;
+            },
+            get pagination() {
+                return {
+                    total: mockTotal,
+                    limit,
+                    offset,
+                    hasMore,
+                    page,
+                    totalPages,
+                };
+            },
+            // Category getters
+            get sansSerifFonts() {
+                return mockFonts.filter(f => f.category === 'sans-serif');
+            },
+            get serifFonts() {
+                return mockFonts.filter(f => f.category === 'serif');
+            },
+            get displayFonts() {
+                return mockFonts.filter(f => f.category === 'display');
+            },
+            get handwritingFonts() {
+                return mockFonts.filter(f => f.category === 'handwriting');
+            },
+            get monospaceFonts() {
+                return mockFonts.filter(f => f.category === 'monospace');
+            },
+            // Lifecycle
+            destroy() {},
+            // Param management
+            setParams(_updates: Record<string, unknown>) {},
+            invalidate() {},
+            // Async operations (no-op for Storybook)
+            refetch() {},
+            prefetch() {},
+            cancel() {},
+            getCachedData() {
+                return mockFonts.length > 0 ? mockFonts : undefined;
+            },
+            setQueryData() {},
+            // Filter shortcuts
+            setProviders() {},
+            setCategories() {},
+            setSubsets() {},
+            setSearch() {},
+            setSort() {},
+            // Pagination navigation
+            nextPage() {},
+            prevPage() {},
+            goToPage() {},
+            setLimit(_limit: number) {
+                state.params.limit = _limit;
+            },
+        };
+    },
 };
 
 // REACTIVE STATE MOCKS

src/entities/Font/model/index.ts

@@ -1,44 +1,7 @@
-export type {
-    // Domain types
-    FontCategory,
-    FontCollectionFilters,
-    FontCollectionSort,
-    // Store types
-    FontCollectionState,
-    FontFeatures,
-    FontFiles,
-    FontItem,
-    FontLoadRequestConfig,
-    FontLoadStatus,
-    FontMetadata,
-    FontProvider,
-    // Fontshare API types
-    FontshareApiModel,
-    FontshareAxis,
-    FontshareDesigner,
-    FontshareFeature,
-    FontshareFont,
-    FontshareLink,
-    FontsharePublisher,
-    FontshareStyle,
-    FontshareStyleProperties,
-    FontshareTag,
-    FontshareWeight,
-    FontStyleUrls,
-    FontSubset,
-    FontVariant,
-    FontWeight,
-    FontWeightItalic,
-    // Google Fonts API types
-    GoogleFontsApiModel,
-    // Normalization types
-    UnifiedFont,
-    UnifiedFontVariant,
-} from './types';
-
 export {
     appliedFontsManager,
-    createUnifiedFontStore,
-    type UnifiedFontStore,
-    unifiedFontStore,
+    createFontStore,
+    FontStore,
+    fontStore,
 } from './store';
+export * from './types';

src/entities/Font/model/store/baseFontStore/baseFontStore.svelte.spec.ts

@@ -1,644 +0,0 @@
-import { QueryClient } from '@tanstack/query-core';
-import { flushSync } from 'svelte';
-import {
-    afterEach,
-    beforeEach,
-    describe,
-    expect,
-    it,
-    vi,
-} from 'vitest';
-import { generateMockFonts } from '../../../lib/mocks/fonts.mock';
-import type { UnifiedFont } from '../../types';
-import { BaseFontStore } from './baseFontStore.svelte';
-
-vi.mock('$shared/api/queryClient', () => ({
-    queryClient: new QueryClient({
-        defaultOptions: {
-            queries: {
-                retry: 0,
-                gcTime: 0,
-            },
-        },
-    }),
-}));
-
-import { queryClient } from '$shared/api/queryClient';
-
-interface TestParams {
-    limit?: number;
-    offset?: number;
-    q?: string;
-    providers?: string[];
-    categories?: string[];
-    subsets?: string[];
-}
-
-class TestFontStore extends BaseFontStore<TestParams> {
-    protected getQueryKey(params: TestParams) {
-        return ['testFonts', params] as const;
-    }
-
-    protected async fetchFn(params: TestParams): Promise<UnifiedFont[]> {
-        return generateMockFonts(params.limit || 10);
-    }
-}
-
-describe('baseFontStore', () => {
-    describe('constructor', () => {
-        afterEach(() => {
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('creates a new store with initial params', () => {
-            const store = new TestFontStore({ limit: 20, offset: 10 });
-
-            expect(store.params.limit).toBe(20);
-            expect(store.params.offset).toBe(10);
-            store.destroy();
-        });
-
-        it('defaults offset to 0 if not provided', () => {
-            const store = new TestFontStore({ limit: 10 });
-
-            expect(store.params.offset).toBe(0);
-            store.destroy();
-        });
-
-        it('initializes observer with query options', () => {
-            const store = new TestFontStore({ limit: 10 });
-
-            expect((store as any).observer).toBeDefined();
-            store.destroy();
-        });
-    });
-
-    describe('params getter', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10, offset: 0 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('returns merged internal params', () => {
-            store.setParams({ limit: 20 });
-            flushSync();
-
-            expect(store.params.limit).toBe(20);
-            expect(store.params.offset).toBe(0);
-        });
-
-        it('defaults offset to 0 when undefined', () => {
-            const store2 = new TestFontStore({});
-            flushSync();
-
-            expect(store2.params.offset).toBe(0);
-            store2.destroy();
-        });
-    });
-
-    describe('state getters', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        describe('fonts', () => {
-            it('returns fonts after auto-fetch on mount', async () => {
-                await new Promise(resolve => setTimeout(resolve, 0));
-
-                expect(store.fonts).toHaveLength(10);
-            });
-
-            it('returns fonts when data is loaded', async () => {
-                await store.refetch();
-                flushSync();
-
-                expect(store.fonts).toHaveLength(10);
-            });
-
-            it('returns fonts when data is loaded', async () => {
-                await store.refetch();
-                flushSync();
-
-                expect(store.fonts).toHaveLength(10);
-            });
-        });
-
-        describe('isLoading', () => {
-            it('is false after initial fetch completes', async () => {
-                await store.refetch();
-                flushSync();
-
-                expect(store.isLoading).toBe(false);
-            });
-
-            it('is false when error occurs', async () => {
-                vi.spyOn(store, 'fetchFn' as any).mockRejectedValue(new Error('fail'));
-                await store.refetch().catch(() => {});
-                flushSync();
-
-                expect(store.isLoading).toBe(false);
-            });
-        });
-
-        describe('isFetching', () => {
-            it('is false after fetch completes', async () => {
-                await store.refetch();
-                flushSync();
-
-                expect(store.isFetching).toBe(false);
-            });
-
-            it('is true during refetch', async () => {
-                await store.refetch();
-                flushSync();
-
-                const refetchPromise = store.refetch();
-                flushSync();
-
-                expect(store.isFetching).toBe(true);
-                await refetchPromise;
-            });
-        });
-
-        describe('isError', () => {
-            it('is false initially', () => {
-                expect(store.isError).toBe(false);
-            });
-
-            it('is true after fetch error', async () => {
-                vi.spyOn(store, 'fetchFn' as any).mockRejectedValue(new Error('fail'));
-                await store.refetch().catch(() => {});
-                flushSync();
-
-                expect(store.isError).toBe(true);
-            });
-
-            it('is false after successful fetch', async () => {
-                await store.refetch();
-                flushSync();
-
-                expect(store.isError).toBe(false);
-            });
-        });
-
-        describe('error', () => {
-            it('is null initially', () => {
-                expect(store.error).toBeNull();
-            });
-
-            it('returns error object after fetch error', async () => {
-                const testError = new Error('test error');
-                vi.spyOn(store, 'fetchFn' as any).mockRejectedValue(testError);
-                await store.refetch().catch(() => {});
-                flushSync();
-
-                expect(store.error).toBe(testError);
-            });
-
-            it('is null after successful fetch', async () => {
-                await store.refetch();
-                flushSync();
-
-                expect(store.error).toBeNull();
-            });
-        });
-
-        describe('isEmpty', () => {
-            it('is true when no fonts loaded and not loading', async () => {
-                await store.refetch();
-                flushSync();
-                store.setQueryData(() => []);
-                flushSync();
-
-                expect(store.isEmpty).toBe(true);
-            });
-
-            it('is false when fonts are present', async () => {
-                await store.refetch();
-                flushSync();
-
-                expect(store.isEmpty).toBe(false);
-            });
-
-            it('is false when loading', () => {
-                expect(store.isEmpty).toBe(false);
-            });
-        });
-    });
-
-    describe('setParams', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10, offset: 0 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('merges new params with existing', () => {
-            store.setParams({ limit: 20 });
-            flushSync();
-
-            expect(store.params.limit).toBe(20);
-            expect(store.params.offset).toBe(0);
-        });
-
-        it('replaces existing param values', () => {
-            store.setParams({ limit: 30 });
-            flushSync();
-
-            store.setParams({ limit: 40 });
-            flushSync();
-
-            expect(store.params.limit).toBe(40);
-        });
-
-        it('triggers observer options update', async () => {
-            const setOptionsSpy = vi.spyOn((store as any).observer, 'setOptions');
-
-            store.setParams({ limit: 20 });
-            flushSync();
-
-            expect(setOptionsSpy).toHaveBeenCalled();
-        });
-    });
-
-    describe('updateInternalParams', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10, offset: 20 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('updates internal params without triggering setParams hooks', () => {
-            (store as any).updateInternalParams({ offset: 0 });
-            flushSync();
-
-            expect(store.params.offset).toBe(0);
-            expect(store.params.limit).toBe(10);
-        });
-
-        it('merges with existing internal params', () => {
-            (store as any).updateInternalParams({ offset: 0, limit: 30 });
-            flushSync();
-
-            expect(store.params.offset).toBe(0);
-            expect(store.params.limit).toBe(30);
-        });
-
-        it('updates observer options', () => {
-            const setOptionsSpy = vi.spyOn((store as any).observer, 'setOptions');
-
-            (store as any).updateInternalParams({ offset: 0 });
-            flushSync();
-
-            expect(setOptionsSpy).toHaveBeenCalled();
-        });
-    });
-
-    describe('invalidate', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('invalidates query for current params', async () => {
-            await store.refetch();
-            flushSync();
-
-            const invalidateSpy = vi.spyOn(queryClient, 'invalidateQueries');
-            store.invalidate();
-
-            expect(invalidateSpy).toHaveBeenCalledWith({
-                queryKey: ['testFonts', store.params],
-            });
-        });
-
-        it('triggers refetch of invalidated query', async () => {
-            await store.refetch();
-            flushSync();
-
-            const fetchSpy = vi.spyOn(store, 'fetchFn' as any);
-            store.invalidate();
-            await store.refetch();
-            flushSync();
-
-            expect(fetchSpy).toHaveBeenCalled();
-        });
-    });
-
-    describe('destroy', () => {
-        it('calls cleanup function', () => {
-            const store = new TestFontStore({ limit: 10 });
-            const cleanupSpy = vi.spyOn(store, 'cleanup' as any);
-
-            store.destroy();
-
-            expect(cleanupSpy).toHaveBeenCalled();
-        });
-
-        it('can be called multiple times without error', () => {
-            const store = new TestFontStore({ limit: 10 });
-
-            expect(() => {
-                store.destroy();
-                store.destroy();
-            }).not.toThrow();
-        });
-    });
-
-    describe('refetch', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('triggers a refetch', async () => {
-            const fetchSpy = vi.spyOn(store, 'fetchFn' as any);
-            await store.refetch();
-            flushSync();
-
-            expect(fetchSpy).toHaveBeenCalled();
-        });
-
-        it('updates observer options before refetching', async () => {
-            const setOptionsSpy = vi.spyOn((store as any).observer, 'setOptions');
-            const refetchSpy = vi.spyOn((store as any).observer, 'refetch');
-
-            await store.refetch();
-            flushSync();
-
-            expect(setOptionsSpy).toHaveBeenCalledBefore(refetchSpy);
-        });
-
-        it('uses current params for refetch', async () => {
-            store.setParams({ limit: 20 });
-            flushSync();
-
-            await store.refetch();
-            flushSync();
-
-            expect(store.params.limit).toBe(20);
-        });
-    });
-
-    describe('prefetch', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('prefetches data with provided params', async () => {
-            const prefetchSpy = vi.spyOn(queryClient, 'prefetchQuery');
-
-            await store.prefetch({ limit: 20, offset: 0 });
-
-            expect(prefetchSpy).toHaveBeenCalled();
-        });
-
-        it('stores prefetched data in cache', async () => {
-            queryClient.clear();
-
-            const store2 = new TestFontStore({ limit: 10 });
-            await store2.prefetch({ limit: 5, offset: 0 });
-            flushSync();
-
-            const cached = store2.getCachedData();
-            expect(cached).toBeDefined();
-            expect(cached?.length).toBeGreaterThanOrEqual(0);
-            store2.destroy();
-        });
-    });
-
-    describe('cancel', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('cancels ongoing queries', () => {
-            const cancelSpy = vi.spyOn(queryClient, 'cancelQueries');
-
-            store.cancel();
-
-            expect(cancelSpy).toHaveBeenCalledWith({
-                queryKey: ['testFonts', store.params],
-            });
-        });
-    });
-
-    describe('getCachedData', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('returns undefined when no data cached', () => {
-            queryClient.clear();
-
-            const store2 = new TestFontStore({ limit: 10 });
-            expect(store2.getCachedData()).toBeUndefined();
-            store2.destroy();
-        });
-
-        it('returns cached data after fetch', async () => {
-            await store.refetch();
-            flushSync();
-
-            const cached = store.getCachedData();
-            expect(cached).toHaveLength(10);
-        });
-
-        it('returns data from manual cache update', () => {
-            store.setQueryData(() => [generateMockFonts(1)[0]]);
-            flushSync();
-
-            const cached = store.getCachedData();
-            expect(cached).toHaveLength(1);
-        });
-    });
-
-    describe('setQueryData', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('sets data in cache', () => {
-            store.setQueryData(() => [generateMockFonts(1)[0]]);
-            flushSync();
-
-            const cached = store.getCachedData();
-            expect(cached).toHaveLength(1);
-        });
-
-        it('updates existing cached data', async () => {
-            await store.refetch();
-            flushSync();
-
-            store.setQueryData(old => [...(old || []), generateMockFonts(1)[0]]);
-            flushSync();
-
-            const cached = store.getCachedData();
-            expect(cached).toHaveLength(11);
-        });
-
-        it('receives previous data in updater function', async () => {
-            await store.refetch();
-            flushSync();
-
-            const updater = vi.fn((old: UnifiedFont[] | undefined) => old || []);
-            store.setQueryData(updater);
-            flushSync();
-
-            expect(updater).toHaveBeenCalledWith(expect.any(Array));
-        });
-    });
-
-    describe('getOptions', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('returns query options with query key', () => {
-            const options = (store as any).getOptions();
-
-            expect(options.queryKey).toEqual(['testFonts', store.params]);
-        });
-
-        it('returns query options with query fn', () => {
-            const options = (store as any).getOptions();
-
-            expect(options.queryFn).toBeDefined();
-        });
-
-        it('uses provided params when passed', () => {
-            const customParams = { limit: 20, offset: 0 };
-            const options = (store as any).getOptions(customParams);
-
-            expect(options.queryKey).toEqual(['testFonts', customParams]);
-        });
-
-        it('has default staleTime and gcTime', () => {
-            const options = (store as any).getOptions();
-
-            expect(options.staleTime).toBe(5 * 60 * 1000);
-            expect(options.gcTime).toBe(10 * 60 * 1000);
-        });
-    });
-
-    describe('observer integration', () => {
-        let store: TestFontStore;
-
-        beforeEach(() => {
-            store = new TestFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('syncs observer state to Svelte state', async () => {
-            await store.refetch();
-            flushSync();
-
-            expect(store.fonts).toHaveLength(10);
-        });
-
-        it('observer syncs on state changes', async () => {
-            await store.refetch();
-            flushSync();
-
-            expect((store as any).result.data).toHaveLength(10);
-        });
-    });
-
-    describe('effect cleanup', () => {
-        it('cleanup function is set on constructor', () => {
-            const store = new TestFontStore({ limit: 10 });
-
-            expect(store.cleanup).toBeDefined();
-            expect(typeof store.cleanup).toBe('function');
-
-            store.destroy();
-        });
-    });
-});

src/entities/Font/model/store/baseFontStore/baseFontStore.svelte.ts

@@ -1,206 +0,0 @@
-import { queryClient } from '$shared/api/queryClient';
-import {
-    type QueryKey,
-    QueryObserver,
-    type QueryObserverOptions,
-    type QueryObserverResult,
-} from '@tanstack/query-core';
-import type { UnifiedFont } from '../../types';
-
-/**
- * Base class for font stores using TanStack Query
- *
- * Provides reactive font data fetching with caching, automatic refetching,
- * and parameter binding. Extended by UnifiedFontStore for provider-agnostic
- * font fetching.
- *
- * @template TParams - Type of query parameters
- */
-export abstract class BaseFontStore<TParams extends Record<string, any>> {
-    /**
-     * Cleanup function for effects
-     * Call destroy() to remove effects and prevent memory leaks
-     */
-    cleanup: () => void;
-
-    /** Internal parameter state */
-    #internalParams = $state<TParams>({} as TParams);
-
-    /**
-     * Merged params from internal state
-     * Computed synchronously on access
-     */
-    get params(): TParams {
-        // Default offset to 0 if undefined (for pagination methods)
-        let result = this.#internalParams as TParams;
-        if (result.offset === undefined) {
-            result = { ...result, offset: 0 } as TParams;
-        }
-
-        return result;
-    }
-
-    /** TanStack Query result state */
-    protected result = $state<QueryObserverResult<UnifiedFont[], Error>>({} as any);
-    /** TanStack Query observer instance */
-    protected observer: QueryObserver<UnifiedFont[], Error>;
-    /** Shared query client */
-    protected qc = queryClient;
-
-    /**
-     * Creates a new base font store
-     * @param initialParams - Initial query parameters
-     */
-    constructor(initialParams: TParams) {
-        this.#internalParams = initialParams;
-
-        this.observer = new QueryObserver(this.qc, this.getOptions());
-
-        // Sync TanStack Query state -> Svelte state
-        this.observer.subscribe(r => {
-            this.result = r;
-        });
-
-        // Sync Svelte state changes -> TanStack Query options
-        this.cleanup = $effect.root(() => {
-            $effect(() => {
-                this.observer.setOptions(this.getOptions());
-            });
-        });
-    }
-
-    /**
-     * Must be implemented by child class
-     * Returns the query key for TanStack Query caching
-     */
-    protected abstract getQueryKey(params: TParams): QueryKey;
-
-    /**
-     * Must be implemented by child class
-     * Fetches font data from API
-     */
-    protected abstract fetchFn(params: TParams): Promise<UnifiedFont[]>;
-
-    /**
-     * Gets TanStack Query options
-     * @param params - Query parameters (defaults to current params)
-     */
-    protected getOptions(params = this.params): QueryObserverOptions<UnifiedFont[], Error> {
-        // Always use current params, not the captured closure params
-        return {
-            queryKey: this.getQueryKey(params),
-            queryFn: () => this.fetchFn(this.params),
-            staleTime: 5 * 60 * 1000,
-            gcTime: 10 * 60 * 1000,
-        };
-    }
-
-    /** Array of fonts (empty array if loading/error) */
-    get fonts() {
-        return this.result.data ?? [];
-    }
-
-    /** Whether currently fetching initial data */
-    get isLoading() {
-        return this.result.isLoading;
-    }
-
-    /** Whether any fetch is in progress (including refetches) */
-    get isFetching() {
-        return this.result.isFetching;
-    }
-
-    /** Whether last fetch resulted in an error */
-    get isError() {
-        return this.result.isError;
-    }
-
-    /** The error from the last failed fetch, or null if no error. */
-    get error(): Error | null {
-        return this.result.error ?? null;
-    }
-
-    /** Whether no fonts are loaded (not loading and empty array) */
-    get isEmpty() {
-        return !this.isLoading && this.fonts.length === 0;
-    }
-
-    /**
-     * Update query parameters
-     * @param newParams - Partial params to merge with existing
-     */
-    setParams(newParams: Partial<TParams>) {
-        this.#internalParams = { ...this.#internalParams, ...newParams };
-        // Manually update observer options since effects may not run in test contexts
-        this.observer.setOptions(this.getOptions());
-    }
-
-    /**
-     * Update internal params without triggering setParams hooks
-     * Used for resetting offset when filters change
-     * @param newParams - Partial params to merge with existing
-     */
-    protected updateInternalParams(newParams: Partial<TParams>) {
-        this.#internalParams = { ...this.#internalParams, ...newParams };
-        // Update observer options
-        this.observer.setOptions(this.getOptions());
-    }
-
-    /**
-     * Invalidate cache and refetch
-     */
-    invalidate() {
-        this.qc.invalidateQueries({ queryKey: this.getQueryKey(this.params) });
-    }
-
-    /**
-     * Clean up effects and observers
-     */
-    destroy() {
-        this.cleanup();
-    }
-
-    /**
-     * Manually trigger a refetch
-     */
-    async refetch() {
-        // Update options before refetching to ensure current params are used
-        this.observer.setOptions(this.getOptions());
-        await this.observer.refetch();
-    }
-
-    /**
-     * Prefetch data with different parameters
-     */
-    async prefetch(params: TParams) {
-        await this.qc.prefetchQuery(this.getOptions(params));
-    }
-
-    /**
-     * Cancel ongoing queries
-     */
-    cancel() {
-        this.qc.cancelQueries({
-            queryKey: this.getQueryKey(this.params),
-        });
-    }
-
-    /**
-     * Get cached data without triggering fetch
-     */
-    getCachedData() {
-        return this.qc.getQueryData<UnifiedFont[]>(
-            this.getQueryKey(this.params),
-        );
-    }
-
-    /**
-     * Set data manually (optimistic updates)
-     */
-    setQueryData(updater: (old: UnifiedFont[] | undefined) => UnifiedFont[]) {
-        this.qc.setQueryData(
-            this.getQueryKey(this.params),
-            updater,
-        );
-    }
-}

src/entities/Font/model/store/fontStore/fontStore.svelte.spec.ts

@@ -0,0 +1,583 @@
+import { QueryClient } from '@tanstack/query-core';
+import { flushSync } from 'svelte';
+import {
+    afterEach,
+    beforeEach,
+    describe,
+    expect,
+    it,
+    vi,
+} from 'vitest';
+import {
+    FontNetworkError,
+    FontResponseError,
+} from '../../../lib/errors/errors';
+import {
+    generateMixedCategoryFonts,
+    generateMockFonts,
+} from '../../../lib/mocks/fonts.mock';
+import type { UnifiedFont } from '../../types';
+import { FontStore } from './fontStore.svelte';
+
+vi.mock('$shared/api/queryClient', () => ({
+    queryClient: new QueryClient({
+        defaultOptions: { queries: { retry: 0, gcTime: 0 } },
+    }),
+}));
+vi.mock('../../../api', () => ({ fetchProxyFonts: vi.fn() }));
+
+import { queryClient } from '$shared/api/queryClient';
+import { fetchProxyFonts } from '../../../api';
+
+const fetch = fetchProxyFonts as ReturnType<typeof vi.fn>;
+
+type FontPage = { fonts: UnifiedFont[]; total: number; limit: number; offset: number };
+
+const makeResponse = (
+    fonts: UnifiedFont[],
+    meta: { total?: number; limit?: number; offset?: number } = {},
+): FontPage => ({
+    fonts,
+    total: meta.total ?? fonts.length,
+    limit: meta.limit ?? 10,
+    offset: meta.offset ?? 0,
+});
+
+function makeStore(params = {}) {
+    return new FontStore({ limit: 10, ...params });
+}
+
+async function fetchedStore(params = {}, fonts = generateMockFonts(5), meta: Parameters<typeof makeResponse>[1] = {}) {
+    fetch.mockResolvedValue(makeResponse(fonts, meta));
+    const store = makeStore(params);
+    await store.refetch();
+    flushSync();
+    return store;
+}
+
+describe('FontStore', () => {
+    afterEach(() => {
+        queryClient.clear();
+        vi.resetAllMocks();
+    });
+
+    // -----------------------------------------------------------------------
+    describe('construction', () => {
+        it('stores initial params', () => {
+            const store = makeStore({ limit: 20 });
+            expect(store.params.limit).toBe(20);
+            store.destroy();
+        });
+
+        it('defaults limit to 50 when not provided', () => {
+            const store = new FontStore();
+            expect(store.params.limit).toBe(50);
+            store.destroy();
+        });
+
+        it('starts with empty fonts', () => {
+            const store = makeStore();
+            expect(store.fonts).toEqual([]);
+            store.destroy();
+        });
+
+        it('starts with isEmpty false — initial fetch is in progress', () => {
+            // The observer starts fetching immediately on construction.
+            // isEmpty must be false so the UI shows a loader, not "no results".
+            const store = makeStore();
+            expect(store.isEmpty).toBe(false);
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('state after fetch', () => {
+        it('exposes loaded fonts', async () => {
+            const store = await fetchedStore({}, generateMockFonts(7));
+            expect(store.fonts).toHaveLength(7);
+            store.destroy();
+        });
+
+        it('isEmpty is false when fonts are present', async () => {
+            const store = await fetchedStore();
+            expect(store.isEmpty).toBe(false);
+            store.destroy();
+        });
+
+        it('isLoading is false after fetch', async () => {
+            const store = await fetchedStore();
+            expect(store.isLoading).toBe(false);
+            store.destroy();
+        });
+
+        it('isFetching is false after fetch', async () => {
+            const store = await fetchedStore();
+            expect(store.isFetching).toBe(false);
+            store.destroy();
+        });
+
+        it('isError is false on success', async () => {
+            const store = await fetchedStore();
+            expect(store.isError).toBe(false);
+            store.destroy();
+        });
+
+        it('error is null on success', async () => {
+            const store = await fetchedStore();
+            expect(store.error).toBeNull();
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('error states', () => {
+        it('isError is false before any fetch', () => {
+            const store = makeStore();
+            expect(store.isError).toBe(false);
+            store.destroy();
+        });
+
+        it('wraps network failures in FontNetworkError', async () => {
+            fetch.mockRejectedValue(new Error('network down'));
+            const store = makeStore();
+            await store.refetch().catch(() => {});
+            flushSync();
+            expect(store.error).toBeInstanceOf(FontNetworkError);
+            expect(store.isError).toBe(true);
+            store.destroy();
+        });
+
+        it('exposes FontResponseError for falsy response', async () => {
+            const store = makeStore();
+            fetch.mockResolvedValue(null);
+            await store.refetch().catch(() => {});
+            flushSync();
+            expect(store.error).toBeInstanceOf(FontResponseError);
+            expect((store.error as FontResponseError).field).toBe('response');
+            store.destroy();
+        });
+
+        it('exposes FontResponseError for missing fonts field', async () => {
+            fetch.mockResolvedValue({ total: 0, limit: 10, offset: 0 });
+            const store = makeStore();
+            await store.refetch().catch(() => {});
+            flushSync();
+            expect(store.error).toBeInstanceOf(FontResponseError);
+            expect((store.error as FontResponseError).field).toBe('response.fonts');
+            store.destroy();
+        });
+
+        it('exposes FontResponseError for non-array fonts', async () => {
+            fetch.mockResolvedValue({ fonts: 'bad', total: 0, limit: 10, offset: 0 });
+            const store = makeStore();
+            await store.refetch().catch(() => {});
+            flushSync();
+            expect(store.error).toBeInstanceOf(FontResponseError);
+            expect((store.error as FontResponseError).received).toBe('bad');
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('font accumulation', () => {
+        it('replaces fonts when refetching the first page', async () => {
+            const store = makeStore();
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(3)));
+            await store.refetch();
+            flushSync();
+
+            const second = generateMockFonts(2);
+            fetch.mockResolvedValue(makeResponse(second));
+            await store.refetch();
+            flushSync();
+
+            // refetch at offset=0 re-fetches all pages; only one page loaded → new data replaces old
+            expect(store.fonts).toHaveLength(2);
+            expect(store.fonts[0].id).toBe(second[0].id);
+            store.destroy();
+        });
+
+        it('appends fonts after nextPage', async () => {
+            const page1 = generateMockFonts(3);
+            const store = await fetchedStore({ limit: 3 }, page1, { total: 6, limit: 3, offset: 0 });
+            const page2 = generateMockFonts(3).map((f, i) => ({ ...f, id: `p2-${i}` }));
+            fetch.mockResolvedValue(makeResponse(page2, { total: 6, limit: 3, offset: 3 }));
+            await store.nextPage();
+            flushSync();
+
+            expect(store.fonts).toHaveLength(6);
+            expect(store.fonts.slice(0, 3).map(f => f.id)).toEqual(page1.map(f => f.id));
+            expect(store.fonts.slice(3).map(f => f.id)).toEqual(page2.map(f => f.id));
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('pagination state', () => {
+        it('returns zero-value defaults before any fetch', () => {
+            const store = makeStore();
+            expect(store.pagination).toMatchObject({ total: 0, hasMore: false, page: 1, totalPages: 0 });
+            store.destroy();
+        });
+
+        it('reflects response metadata after fetch', async () => {
+            const store = await fetchedStore({}, generateMockFonts(10), { total: 30, limit: 10, offset: 0 });
+            expect(store.pagination.total).toBe(30);
+            expect(store.pagination.hasMore).toBe(true);
+            expect(store.pagination.page).toBe(1);
+            expect(store.pagination.totalPages).toBe(3);
+            store.destroy();
+        });
+
+        it('hasMore is false on the last page', async () => {
+            const store = await fetchedStore({}, generateMockFonts(10), { total: 10, limit: 10, offset: 0 });
+            expect(store.pagination.hasMore).toBe(false);
+            store.destroy();
+        });
+
+        it('page count increments after nextPage', async () => {
+            const store = await fetchedStore({ limit: 10 }, generateMockFonts(10), { total: 30, limit: 10, offset: 0 });
+            expect(store.pagination.page).toBe(1);
+
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 30, limit: 10, offset: 10 }));
+            await store.nextPage();
+            flushSync();
+            expect(store.pagination.page).toBe(2);
+
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('setParams', () => {
+        it('merges updates into existing params', () => {
+            const store = makeStore({ limit: 10 });
+            store.setParams({ limit: 20 });
+            expect(store.params.limit).toBe(20);
+            store.destroy();
+        });
+
+        it('retains unmodified params', () => {
+            const store = makeStore({ limit: 10 });
+            store.setCategories(['serif']);
+            store.setParams({ limit: 25 });
+            expect(store.params.categories).toEqual(['serif']);
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('filter change resets', () => {
+        it('clears accumulated fonts when a filter changes', async () => {
+            const store = await fetchedStore({}, generateMockFonts(5));
+            store.setSearch('roboto');
+            flushSync();
+            // TQ switches to a new queryKey → data.pages reset → fonts = []
+            expect(store.fonts).toHaveLength(0);
+            store.destroy();
+        });
+
+        it('isEmpty is false immediately after filter change — fetch is in progress', async () => {
+            const store = await fetchedStore({}, generateMockFonts(5));
+            // Hang the next fetch so we can observe the transitioning state
+            fetch.mockReturnValue(new Promise(() => {}));
+            store.setSearch('roboto');
+            flushSync();
+            // fonts = [] AND isFetching = true → isEmpty must be false (no "no results" flash)
+            expect(store.isEmpty).toBe(false);
+            store.destroy();
+        });
+
+        it('does NOT reset fonts when the same filter value is set again', async () => {
+            const store = await fetchedStore({}, generateMockFonts(5));
+            store.setCategories(['serif']);
+            flushSync();
+            // First change: clears fonts (expected)
+            store.setCategories(['serif']); // same value — same queryKey — TQ keeps data.pages
+            flushSync();
+            // Because queryKey hasn't changed, TQ returns cached data — fonts restored from cache
+            // (actual font count depends on cache; key assertion is no extra reset)
+            expect(store.isError).toBe(false);
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('staleTime in buildOptions', () => {
+        it('is 5 minutes with no active filters', () => {
+            const store = makeStore();
+            expect((store as any).buildOptions().staleTime).toBe(5 * 60 * 1000);
+            store.destroy();
+        });
+
+        it('is 0 when a search query is active', () => {
+            const store = makeStore();
+            store.setSearch('roboto');
+            expect((store as any).buildOptions().staleTime).toBe(0);
+            store.destroy();
+        });
+
+        it('is 0 when a category filter is active', () => {
+            const store = makeStore();
+            store.setCategories(['serif']);
+            expect((store as any).buildOptions().staleTime).toBe(0);
+            store.destroy();
+        });
+
+        it('gcTime is 10 minutes always', () => {
+            const store = makeStore();
+            expect((store as any).buildOptions().gcTime).toBe(10 * 60 * 1000);
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('buildQueryKey', () => {
+        it('omits empty-string params', () => {
+            const store = makeStore();
+            store.setSearch('');
+            const [root, normalized] = (store as any).buildQueryKey(store.params);
+            expect(root).toBe('fonts');
+            expect(normalized).not.toHaveProperty('q');
+            store.destroy();
+        });
+
+        it('omits empty-array params', () => {
+            const store = makeStore();
+            store.setProviders([]);
+            const [, normalized] = (store as any).buildQueryKey(store.params);
+            expect(normalized).not.toHaveProperty('providers');
+            store.destroy();
+        });
+
+        it('includes non-empty filter values', () => {
+            const store = makeStore();
+            store.setCategories(['serif']);
+            const [, normalized] = (store as any).buildQueryKey(store.params);
+            expect(normalized).toHaveProperty('categories', ['serif']);
+            store.destroy();
+        });
+
+        it('does not include offset (offset is the TQ page param, not a query key component)', () => {
+            const store = makeStore();
+            const [, normalized] = (store as any).buildQueryKey(store.params);
+            expect(normalized).not.toHaveProperty('offset');
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('destroy', () => {
+        it('does not throw', () => {
+            const store = makeStore();
+            expect(() => store.destroy()).not.toThrow();
+        });
+
+        it('is idempotent', () => {
+            const store = makeStore();
+            store.destroy();
+            expect(() => store.destroy()).not.toThrow();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('refetch', () => {
+        it('triggers a fetch', async () => {
+            const store = makeStore();
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(3)));
+            await store.refetch();
+            expect(fetch).toHaveBeenCalled();
+            store.destroy();
+        });
+
+        it('uses params current at call time', async () => {
+            const store = makeStore({ limit: 10 });
+            store.setParams({ limit: 20 });
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(20)));
+            await store.refetch();
+            expect(fetch).toHaveBeenCalledWith(expect.objectContaining({ limit: 20 }));
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('nextPage', () => {
+        let store: FontStore;
+
+        beforeEach(async () => {
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 30, limit: 10, offset: 0 }));
+            store = new FontStore({ limit: 10 });
+            await store.refetch();
+            flushSync();
+        });
+
+        afterEach(() => {
+            store.destroy();
+        });
+
+        it('fetches the next page and appends fonts', async () => {
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 30, limit: 10, offset: 10 }));
+            await store.nextPage();
+            flushSync();
+            expect(store.fonts).toHaveLength(20);
+            expect(store.pagination.offset).toBe(10);
+        });
+
+        it('is a no-op when hasMore is false', async () => {
+            // Set up a store where all fonts fit in one page (hasMore = false)
+            queryClient.clear();
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 10, limit: 10, offset: 0 }));
+            store = new FontStore({ limit: 10 });
+            await store.refetch();
+            flushSync();
+
+            expect(store.pagination.hasMore).toBe(false);
+            await store.nextPage(); // should not trigger another fetch
+            expect(store.fonts).toHaveLength(10);
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('prevPage and goToPage', () => {
+        it('prevPage is a no-op — infinite scroll does not support backward navigation', async () => {
+            const store = await fetchedStore({}, generateMockFonts(5));
+            store.prevPage();
+            expect(store.fonts).toHaveLength(5); // unchanged
+            store.destroy();
+        });
+
+        it('goToPage is a no-op — infinite scroll does not support arbitrary page jumps', async () => {
+            const store = await fetchedStore({}, generateMockFonts(5));
+            store.goToPage(3);
+            expect(store.fonts).toHaveLength(5); // unchanged
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('prefetch', () => {
+        it('triggers a fetch for the provided params', async () => {
+            const store = makeStore();
+            fetch.mockResolvedValue(makeResponse(generateMockFonts(5)));
+            await store.prefetch({ limit: 5 });
+            expect(fetch).toHaveBeenCalledWith(expect.objectContaining({ limit: 5, offset: 0 }));
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('getCachedData / setQueryData', () => {
+        it('getCachedData returns undefined before any fetch', () => {
+            queryClient.clear();
+            const store = new FontStore({ limit: 10 });
+            expect(store.getCachedData()).toBeUndefined();
+            store.destroy();
+        });
+
+        it('getCachedData returns flattened fonts after fetch', async () => {
+            const store = await fetchedStore();
+            expect(store.getCachedData()).toHaveLength(5);
+            store.destroy();
+        });
+
+        it('setQueryData writes to cache', () => {
+            const store = makeStore();
+            const font = generateMockFonts(1)[0];
+            store.setQueryData(() => [font]);
+            expect(store.getCachedData()).toHaveLength(1);
+            store.destroy();
+        });
+
+        it('setQueryData updater receives existing flattened fonts', async () => {
+            const store = await fetchedStore();
+            const updater = vi.fn((old: UnifiedFont[] | undefined) => old ?? []);
+            store.setQueryData(updater);
+            expect(updater).toHaveBeenCalledWith(expect.any(Array));
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('invalidate', () => {
+        it('calls invalidateQueries', async () => {
+            const store = await fetchedStore();
+            const spy = vi.spyOn(queryClient, 'invalidateQueries');
+            store.invalidate();
+            expect(spy).toHaveBeenCalledOnce();
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('setLimit', () => {
+        it('updates the limit param', () => {
+            const store = makeStore({ limit: 10 });
+            store.setLimit(25);
+            expect(store.params.limit).toBe(25);
+            store.destroy();
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('filter shortcut methods', () => {
+        let store: FontStore;
+
+        beforeEach(() => {
+            store = makeStore();
+        });
+        afterEach(() => {
+            store.destroy();
+        });
+
+        it('setProviders updates providers param', () => {
+            store.setProviders(['google']);
+            expect(store.params.providers).toEqual(['google']);
+        });
+
+        it('setCategories updates categories param', () => {
+            store.setCategories(['serif']);
+            expect(store.params.categories).toEqual(['serif']);
+        });
+
+        it('setSubsets updates subsets param', () => {
+            store.setSubsets(['cyrillic']);
+            expect(store.params.subsets).toEqual(['cyrillic']);
+        });
+
+        it('setSearch sets q param', () => {
+            store.setSearch('roboto');
+            expect(store.params.q).toBe('roboto');
+        });
+
+        it('setSearch with empty string clears q', () => {
+            store.setSearch('roboto');
+            store.setSearch('');
+            expect(store.params.q).toBeUndefined();
+        });
+
+        it('setSort updates sort param', () => {
+            store.setSort('popularity');
+            expect(store.params.sort).toBe('popularity');
+        });
+    });
+
+    // -----------------------------------------------------------------------
+    describe('category getters', () => {
+        it('each getter returns only fonts of that category', async () => {
+            const fonts = generateMixedCategoryFonts(2); // 2 of each category = 10 total
+            fetch.mockResolvedValue(makeResponse(fonts, { total: fonts.length, limit: fonts.length }));
+            const store = makeStore({ limit: 50 });
+            await store.refetch();
+            flushSync();
+
+            expect(store.sansSerifFonts.every(f => f.category === 'sans-serif')).toBe(true);
+            expect(store.serifFonts.every(f => f.category === 'serif')).toBe(true);
+            expect(store.displayFonts.every(f => f.category === 'display')).toBe(true);
+            expect(store.handwritingFonts.every(f => f.category === 'handwriting')).toBe(true);
+            expect(store.monospaceFonts.every(f => f.category === 'monospace')).toBe(true);
+            expect(store.sansSerifFonts).toHaveLength(2);
+
+            store.destroy();
+        });
+    });
+});

src/entities/Font/model/store/fontStore/fontStore.svelte.ts

@@ -0,0 +1,283 @@
+import { queryClient } from '$shared/api/queryClient';
+import {
+    type InfiniteData,
+    InfiniteQueryObserver,
+    type InfiniteQueryObserverResult,
+    type QueryFunctionContext,
+} from '@tanstack/query-core';
+import {
+    type ProxyFontsParams,
+    type ProxyFontsResponse,
+    fetchProxyFonts,
+} from '../../../api';
+import {
+    FontNetworkError,
+    FontResponseError,
+} from '../../../lib/errors/errors';
+import type { UnifiedFont } from '../../types';
+
+type PageParam = { offset: number };
+
+/** Filter params + limit — offset is managed by TQ as a page param, not a user param. */
+type FontStoreParams = Omit<ProxyFontsParams, 'offset'>;
+
+type FontStoreResult = InfiniteQueryObserverResult<InfiniteData<ProxyFontsResponse, PageParam>, Error>;
+
+export class FontStore {
+    #params = $state<FontStoreParams>({ limit: 50 });
+    #result = $state<FontStoreResult>({} as FontStoreResult);
+    #observer: InfiniteQueryObserver<
+        ProxyFontsResponse,
+        Error,
+        InfiniteData<ProxyFontsResponse, PageParam>,
+        readonly unknown[],
+        PageParam
+    >;
+    #qc = queryClient;
+    #unsubscribe: () => void;
+
+    constructor(params: FontStoreParams = {}) {
+        this.#params = { limit: 50, ...params };
+        this.#observer = new InfiniteQueryObserver(this.#qc, this.buildOptions());
+        this.#unsubscribe = this.#observer.subscribe(r => {
+            this.#result = r;
+        });
+    }
+
+    // -- Public state --
+
+    get params(): FontStoreParams {
+        return this.#params;
+    }
+    get fonts(): UnifiedFont[] {
+        return this.#result.data?.pages.flatMap((p: ProxyFontsResponse) => p.fonts) ?? [];
+    }
+    get isLoading(): boolean {
+        return this.#result.isLoading;
+    }
+    get isFetching(): boolean {
+        return this.#result.isFetching;
+    }
+    get isError(): boolean {
+        return this.#result.isError;
+    }
+
+    get error(): Error | null {
+        return this.#result.error ?? null;
+    }
+    // isEmpty is false during loading/fetching so the UI never flashes "no results"
+    // while a fetch is in progress. The !isFetching guard is specifically for the filter-change
+    // transition: fonts clear synchronously → isFetching becomes true → isEmpty stays false.
+    get isEmpty(): boolean {
+        return !this.isLoading && !this.isFetching && this.fonts.length === 0;
+    }
+
+    get pagination() {
+        const pages = this.#result.data?.pages;
+        const last = pages?.at(-1);
+        if (!last) {
+            return {
+                total: 0,
+                limit: this.#params.limit ?? 50,
+                offset: 0,
+                hasMore: false,
+                page: 1,
+                totalPages: 0,
+            };
+        }
+        return {
+            total: last.total,
+            limit: last.limit,
+            offset: last.offset,
+            hasMore: this.#result.hasNextPage,
+            page: pages!.length,
+            totalPages: Math.ceil(last.total / last.limit),
+        };
+    }
+
+    // -- Lifecycle --
+
+    destroy() {
+        this.#unsubscribe();
+        this.#observer.destroy();
+    }
+
+    // -- Param management --
+
+    setParams(updates: Partial<FontStoreParams>) {
+        this.#params = { ...this.#params, ...updates };
+        this.#observer.setOptions(this.buildOptions());
+    }
+    invalidate() {
+        this.#qc.invalidateQueries({ queryKey: this.buildQueryKey(this.#params) });
+    }
+
+    // -- Async operations --
+
+    async refetch() {
+        await this.#observer.refetch();
+    }
+
+    async prefetch(params: FontStoreParams) {
+        await this.#qc.prefetchInfiniteQuery(this.buildOptions(params));
+    }
+
+    cancel() {
+        this.#qc.cancelQueries({ queryKey: this.buildQueryKey(this.#params) });
+    }
+
+    getCachedData(): UnifiedFont[] | undefined {
+        const data = this.#qc.getQueryData<InfiniteData<ProxyFontsResponse, PageParam>>(
+            this.buildQueryKey(this.#params),
+        );
+        if (!data) return undefined;
+        return data.pages.flatMap(p => p.fonts);
+    }
+
+    setQueryData(updater: (old: UnifiedFont[] | undefined) => UnifiedFont[]) {
+        const key = this.buildQueryKey(this.#params);
+        this.#qc.setQueryData<InfiniteData<ProxyFontsResponse, PageParam>>(
+            key,
+            old => {
+                const flatFonts = old?.pages.flatMap(p => p.fonts);
+                const newFonts = updater(flatFonts);
+                // Re-distribute the updated fonts back into the existing page structure
+                // Define the first page. If old data exists, we merge into the first page template.
+                const limit = typeof this.#params.limit === 'number' ? this.#params.limit : 50;
+                const template = old?.pages[0] ?? {
+                    total: newFonts.length,
+                    limit,
+                    offset: 0,
+                };
+
+                const updatedPage: ProxyFontsResponse = {
+                    ...template,
+                    fonts: newFonts,
+                    total: newFonts.length, // Synchronize total with the new font count
+                };
+
+                return {
+                    pages: [updatedPage],
+                    pageParams: [{ offset: 0 }],
+                };
+            },
+        );
+    }
+
+    // -- Filter shortcuts --
+
+    setProviders(v: ProxyFontsParams['providers']) {
+        this.setParams({ providers: v });
+    }
+    setCategories(v: ProxyFontsParams['categories']) {
+        this.setParams({ categories: v });
+    }
+    setSubsets(v: ProxyFontsParams['subsets']) {
+        this.setParams({ subsets: v });
+    }
+    setSearch(v: string) {
+        this.setParams({ q: v || undefined });
+    }
+    setSort(v: ProxyFontsParams['sort']) {
+        this.setParams({ sort: v });
+    }
+
+    // -- Pagination navigation --
+
+    async nextPage(): Promise<void> {
+        await this.#observer.fetchNextPage();
+    }
+    prevPage(): void {} // no-op: infinite scroll accumulates forward only; method kept for API compatibility
+    goToPage(_page: number): void {} // no-op
+
+    setLimit(limit: number) {
+        this.setParams({ limit });
+    }
+
+    // -- Category views --
+
+    get sansSerifFonts() {
+        return this.fonts.filter(f => f.category === 'sans-serif');
+    }
+    get serifFonts() {
+        return this.fonts.filter(f => f.category === 'serif');
+    }
+    get displayFonts() {
+        return this.fonts.filter(f => f.category === 'display');
+    }
+    get handwritingFonts() {
+        return this.fonts.filter(f => f.category === 'handwriting');
+    }
+    get monospaceFonts() {
+        return this.fonts.filter(f => f.category === 'monospace');
+    }
+
+    // -- Private helpers (TypeScript-private so tests can spy via `as any`) --
+
+    private buildQueryKey(params: FontStoreParams): readonly unknown[] {
+        const filtered: Record<string, any> = {};
+
+        for (const [key, value] of Object.entries(params)) {
+            // Ensure we DO NOT 'continue' or skip the limit key here.
+            // The limit is a fundamental part of the data identity.
+            if (
+                value !== undefined
+                && value !== null
+                && value !== ''
+                && !(Array.isArray(value) && value.length === 0)
+            ) {
+                filtered[key] = value;
+            }
+        }
+
+        return ['fonts', filtered];
+    }
+
+    private buildOptions(params = this.#params) {
+        const activeParams = { ...params };
+        const hasFilters = !!(
+            activeParams.q
+            || (Array.isArray(activeParams.providers) && activeParams.providers.length > 0)
+            || (Array.isArray(activeParams.categories) && activeParams.categories.length > 0)
+            || (Array.isArray(activeParams.subsets) && activeParams.subsets.length > 0)
+        );
+        return {
+            queryKey: this.buildQueryKey(activeParams),
+            queryFn: ({ pageParam }: QueryFunctionContext<readonly unknown[], PageParam>) =>
+                this.fetchPage({ ...activeParams, ...pageParam }),
+            initialPageParam: { offset: 0 } as PageParam,
+            getNextPageParam: (lastPage: ProxyFontsResponse): PageParam | undefined => {
+                const next = lastPage.offset + lastPage.limit;
+                return next < lastPage.total ? { offset: next } : undefined;
+            },
+            staleTime: hasFilters ? 0 : 5 * 60 * 1000,
+            gcTime: 10 * 60 * 1000,
+        };
+    }
+
+    private async fetchPage(params: ProxyFontsParams): Promise<ProxyFontsResponse> {
+        let response: ProxyFontsResponse;
+        try {
+            response = await fetchProxyFonts(params);
+        } catch (cause) {
+            throw new FontNetworkError(cause);
+        }
+
+        if (!response) throw new FontResponseError('response', response);
+        if (!response.fonts) throw new FontResponseError('response.fonts', response.fonts);
+        if (!Array.isArray(response.fonts)) throw new FontResponseError('response.fonts', response.fonts);
+
+        return {
+            fonts: response.fonts,
+            total: response.total ?? 0,
+            limit: response.limit ?? params.limit ?? 50,
+            offset: response.offset ?? params.offset ?? 0,
+        };
+    }
+}
+
+export function createFontStore(params: FontStoreParams = {}): FontStore {
+    return new FontStore(params);
+}
+
+export const fontStore = new FontStore({ limit: 50 });

src/entities/Font/model/store/index.ts

@@ -6,12 +6,12 @@
  * Single export point for the unified font store infrastructure.
  */
 
-// Primary store (unified)
-export {
-    createUnifiedFontStore,
-    type UnifiedFontStore,
-    unifiedFontStore,
-} from './unifiedFontStore/unifiedFontStore.svelte';
-
 // Applied fonts manager (CSS loading - unchanged)
 export { appliedFontsManager } from './appliedFontsStore/appliedFontsStore.svelte';
+
+// Single FontStore (new implementation)
+export {
+    createFontStore,
+    FontStore,
+    fontStore,
+} from './fontStore/fontStore.svelte';

src/entities/Font/model/store/unifiedFontStore/unifiedFontStore.svelte.spec.ts

@@ -1,474 +0,0 @@
-import { QueryClient } from '@tanstack/query-core';
-import { tick } from 'svelte';
-import {
-    afterEach,
-    beforeEach,
-    describe,
-    expect,
-    it,
-    vi,
-} from 'vitest';
-import {
-    FontNetworkError,
-    FontResponseError,
-} from '../../../lib/errors/errors';
-
-vi.mock('$shared/api/queryClient', () => ({
-    queryClient: new QueryClient({
-        defaultOptions: {
-            queries: {
-                retry: 0,
-                gcTime: 0,
-            },
-        },
-    }),
-}));
-
-vi.mock('../../../api', () => ({
-    fetchProxyFonts: vi.fn(),
-}));
-
-import { queryClient } from '$shared/api/queryClient';
-import { flushSync } from 'svelte';
-import { fetchProxyFonts } from '../../../api';
-import {
-    generateMixedCategoryFonts,
-    generateMockFonts,
-} from '../../../lib/mocks/fonts.mock';
-import type { UnifiedFont } from '../../types';
-import { UnifiedFontStore } from './unifiedFontStore.svelte';
-
-const mockedFetch = fetchProxyFonts as ReturnType<typeof vi.fn>;
-
-const makeResponse = (
-    fonts: UnifiedFont[],
-    meta: { total?: number; limit?: number; offset?: number } = {},
-) => ({
-    fonts,
-    total: meta.total ?? fonts.length,
-    limit: meta.limit ?? 10,
-    offset: meta.offset ?? 0,
-});
-describe('unifiedFontStore', () => {
-    describe('fetchFn — error paths', () => {
-        let store: UnifiedFontStore;
-
-        beforeEach(() => {
-            store = new UnifiedFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('sets isError and error getter when fetchProxyFonts throws', async () => {
-            mockedFetch.mockRejectedValue(new Error('network down'));
-            await store.refetch().catch((e: unknown) => e);
-
-            expect(store.error).toBeInstanceOf(FontNetworkError);
-            expect((store.error as FontNetworkError).cause).toBeInstanceOf(Error);
-            expect(store.isError).toBe(true);
-        });
-
-        it('throws FontResponseError when response is falsy', async () => {
-            mockedFetch.mockResolvedValue(undefined);
-
-            await store.refetch().catch((e: unknown) => e);
-
-            expect(store.error).toBeInstanceOf(FontResponseError);
-            expect((store.error as FontResponseError).field).toBe('response');
-        });
-
-        it('throws FontResponseError when response.fonts is missing', async () => {
-            mockedFetch.mockResolvedValue({ total: 0, limit: 10, offset: 0 });
-
-            await store.refetch().catch((e: unknown) => e);
-
-            expect(store.error).toBeInstanceOf(FontResponseError);
-            expect((store.error as FontResponseError).field).toBe('response.fonts');
-        });
-
-        it('throws FontResponseError when response.fonts is not an array', async () => {
-            mockedFetch.mockResolvedValue({ fonts: 'bad', total: 0, limit: 10, offset: 0 });
-
-            await store.refetch().catch((e: unknown) => e);
-
-            expect(store.error).toBeInstanceOf(FontResponseError);
-            expect((store.error as FontResponseError).field).toBe('response.fonts');
-            expect((store.error as FontResponseError).received).toBe('bad');
-        });
-    });
-
-    describe('fetchFn — success path', () => {
-        let store: UnifiedFontStore;
-
-        beforeEach(() => {
-            store = new UnifiedFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('populates fonts after a successful fetch', async () => {
-            const fonts = generateMockFonts(3);
-            mockedFetch.mockResolvedValue(makeResponse(fonts));
-            await store.refetch();
-
-            expect(store.fonts).toHaveLength(3);
-            expect(store.fonts[0].id).toBe(fonts[0].id);
-        });
-
-        it('stores pagination metadata from response', async () => {
-            const fonts = generateMockFonts(3);
-            mockedFetch.mockResolvedValue(makeResponse(fonts, { total: 30, limit: 10, offset: 0 }));
-            await store.refetch();
-
-            expect(store.pagination.total).toBe(30);
-            expect(store.pagination.limit).toBe(10);
-            expect(store.pagination.offset).toBe(0);
-        });
-
-        it('replaces accumulated fonts on offset-0 fetch', async () => {
-            const first = generateMockFonts(3);
-            mockedFetch.mockResolvedValue(makeResponse(first));
-            await store.refetch();
-            flushSync();
-
-            const second = generateMockFonts(2);
-            mockedFetch.mockResolvedValue(makeResponse(second));
-            await store.refetch();
-            flushSync();
-
-            expect(store.fonts).toHaveLength(2);
-            expect(store.fonts[0].id).toBe(second[0].id);
-        });
-
-        it('appends fonts when fetching at offset > 0', async () => {
-            const firstPage = generateMockFonts(3);
-            mockedFetch.mockResolvedValue(makeResponse(firstPage, { total: 6, limit: 3, offset: 0 }));
-            await store.refetch();
-
-            const secondPage = generateMockFonts(3).map((f, i) => ({
-                ...f,
-                id: `page2-font-${i + 1}`,
-            }));
-            mockedFetch.mockResolvedValue(makeResponse(secondPage, { total: 6, limit: 3, offset: 3 }));
-            store.setParams({ offset: 3 });
-            await store.refetch();
-
-            expect(store.fonts).toHaveLength(6);
-            expect(store.fonts.slice(0, 3).map(f => f.id)).toEqual(firstPage.map(f => f.id));
-            expect(store.fonts.slice(3).map(f => f.id)).toEqual(secondPage.map(f => f.id));
-        });
-    });
-
-    describe('pagination state', () => {
-        let store: UnifiedFontStore;
-
-        beforeEach(() => {
-            store = new UnifiedFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('returns default pagination before any fetch', () => {
-            expect(store.pagination.total).toBe(0);
-            expect(store.pagination.hasMore).toBe(false);
-            expect(store.pagination.page).toBe(1);
-            expect(store.pagination.totalPages).toBe(0);
-        });
-
-        it('computes hasMore as true when more pages remain', async () => {
-            mockedFetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 30, limit: 10, offset: 0 }));
-            await store.refetch();
-
-            expect(store.pagination.hasMore).toBe(true);
-        });
-
-        it('computes hasMore as false on last page', async () => {
-            mockedFetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 20, limit: 10, offset: 10 }));
-            store.setParams({ offset: 10 });
-            await store.refetch();
-
-            expect(store.pagination.hasMore).toBe(false);
-        });
-
-        it('computes page and totalPages from response metadata', async () => {
-            mockedFetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 30, limit: 10, offset: 10 }));
-            store.setParams({ offset: 10 });
-            await store.refetch();
-
-            expect(store.pagination.page).toBe(2);
-            expect(store.pagination.totalPages).toBe(3);
-        });
-    });
-
-    describe('pagination navigation', () => {
-        let store: UnifiedFontStore;
-
-        beforeEach(async () => {
-            mockedFetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 30, limit: 10, offset: 0 }));
-            store = new UnifiedFontStore({ limit: 10 });
-            await tick();
-            await store.refetch();
-            await tick();
-            flushSync();
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('nextPage() advances offset by limit when hasMore', () => {
-            store.nextPage();
-            flushSync();
-
-            expect(store.params.offset).toBe(10);
-        });
-
-        it('nextPage() does nothing when hasMore is false', async () => {
-            mockedFetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 20, limit: 10, offset: 10 }));
-            store.setParams({ offset: 10 });
-            await store.refetch();
-            flushSync();
-
-            store.nextPage();
-            flushSync();
-
-            expect(store.params.offset).toBe(10);
-        });
-
-        it('prevPage() decrements offset by limit when on page > 1', async () => {
-            mockedFetch.mockResolvedValue(makeResponse(generateMockFonts(10), { total: 30, limit: 10, offset: 10 }));
-            store.setParams({ offset: 10 });
-            await store.refetch();
-            flushSync();
-
-            store.prevPage();
-            flushSync();
-
-            expect(store.params.offset).toBe(0);
-        });
-
-        it('prevPage() does nothing on the first page', () => {
-            store.prevPage();
-            flushSync();
-
-            expect(store.params.offset).toBe(0);
-        });
-
-        it('goToPage() sets the correct offset', () => {
-            store.goToPage(2);
-            flushSync();
-
-            expect(store.params.offset).toBe(10);
-        });
-
-        it('goToPage() does nothing for page 0', () => {
-            store.goToPage(0);
-            flushSync();
-
-            expect(store.params.offset).toBe(0);
-        });
-
-        it('goToPage() does nothing for page beyond totalPages', () => {
-            store.goToPage(99);
-            flushSync();
-
-            expect(store.params.offset).toBe(0);
-        });
-
-        it('setLimit() updates the limit param', () => {
-            store.setLimit(25);
-            flushSync();
-
-            expect(store.params.limit).toBe(25);
-        });
-    });
-
-    describe('filter setters', () => {
-        let store: UnifiedFontStore;
-
-        beforeEach(() => {
-            store = new UnifiedFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('setProviders() updates the providers param', () => {
-            store.setProviders(['google']);
-            flushSync();
-
-            expect(store.params.providers).toEqual(['google']);
-        });
-
-        it('setCategories() updates the categories param', () => {
-            store.setCategories(['serif']);
-            flushSync();
-
-            expect(store.params.categories).toEqual(['serif']);
-        });
-
-        it('setSubsets() updates the subsets param', () => {
-            store.setSubsets(['cyrillic']);
-            flushSync();
-
-            expect(store.params.subsets).toEqual(['cyrillic']);
-        });
-
-        it('setSearch() sets the q param', () => {
-            store.setSearch('roboto');
-            flushSync();
-
-            expect(store.params.q).toBe('roboto');
-        });
-
-        it('setSearch() with empty string sets q to undefined', () => {
-            store.setSearch('roboto');
-            store.setSearch('');
-            flushSync();
-
-            expect(store.params.q).toBeUndefined();
-        });
-
-        it('setSort() updates the sort param', () => {
-            store.setSort('popularity');
-            flushSync();
-
-            expect(store.params.sort).toBe('popularity');
-        });
-    });
-
-    describe('filter change resets pagination', () => {
-        let store: UnifiedFontStore;
-
-        beforeEach(() => {
-            store = new UnifiedFontStore({ limit: 10 });
-            flushSync();
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('resets offset to 0 when a filter changes', () => {
-            store.setParams({ offset: 20 });
-            flushSync();
-
-            store.setParams({ q: 'roboto' });
-            flushSync();
-
-            expect(store.params.offset).toBe(0);
-        });
-
-        it('clears accumulated fonts when a filter changes', async () => {
-            const fonts = generateMockFonts(3);
-            mockedFetch.mockResolvedValue(makeResponse(fonts));
-            await store.refetch();
-            flushSync();
-            expect(store.fonts).toHaveLength(3);
-
-            store.setParams({ q: 'roboto' });
-            flushSync();
-
-            expect(store.fonts).toHaveLength(0);
-        });
-    });
-
-    describe('category getters', () => {
-        let store: UnifiedFontStore;
-
-        beforeEach(() => {
-            store = new UnifiedFontStore({ limit: 10 });
-        });
-
-        afterEach(() => {
-            store.destroy();
-            queryClient.clear();
-            vi.resetAllMocks();
-        });
-
-        it('sansSerifFonts returns only sans-serif fonts', async () => {
-            const fonts = generateMixedCategoryFonts(2);
-            mockedFetch.mockResolvedValue(makeResponse(fonts, { total: fonts.length, limit: fonts.length }));
-            await store.refetch();
-
-            expect(store.fonts).toHaveLength(10);
-            expect(store.sansSerifFonts).toHaveLength(2);
-            expect(store.sansSerifFonts.every(f => f.category === 'sans-serif')).toBe(true);
-        });
-
-        it('serifFonts returns only serif fonts', async () => {
-            const fonts = generateMixedCategoryFonts(2);
-            mockedFetch.mockResolvedValue(makeResponse(fonts, { total: fonts.length, limit: fonts.length }));
-            await store.refetch();
-
-            expect(store.serifFonts).toHaveLength(2);
-            expect(store.serifFonts.every(f => f.category === 'serif')).toBe(true);
-        });
-
-        it('displayFonts returns only display fonts', async () => {
-            const fonts = generateMixedCategoryFonts(2);
-            mockedFetch.mockResolvedValue(makeResponse(fonts, { total: fonts.length, limit: fonts.length }));
-            await store.refetch();
-
-            expect(store.displayFonts).toHaveLength(2);
-            expect(store.displayFonts.every(f => f.category === 'display')).toBe(true);
-        });
-
-        it('handwritingFonts returns only handwriting fonts', async () => {
-            const fonts = generateMixedCategoryFonts(2);
-            mockedFetch.mockResolvedValue(makeResponse(fonts, { total: fonts.length, limit: fonts.length }));
-            await store.refetch();
-
-            expect(store.handwritingFonts).toHaveLength(2);
-            expect(store.handwritingFonts.every(f => f.category === 'handwriting')).toBe(true);
-        });
-
-        it('monospaceFonts returns only monospace fonts', async () => {
-            const fonts = generateMixedCategoryFonts(2);
-            mockedFetch.mockResolvedValue(makeResponse(fonts, { total: fonts.length, limit: fonts.length }));
-            await store.refetch();
-
-            expect(store.monospaceFonts).toHaveLength(2);
-            expect(store.monospaceFonts.every(f => f.category === 'monospace')).toBe(true);
-        });
-    });
-
-    describe('destroy', () => {
-        it('calls parent destroy and filterCleanup', () => {
-            const store = new UnifiedFontStore({ limit: 10 });
-            const parentDestroySpy = vi.spyOn(Object.getPrototypeOf(Object.getPrototypeOf(store)), 'destroy');
-
-            store.destroy();
-
-            expect(parentDestroySpy).toHaveBeenCalled();
-        });
-
-        it('can be called multiple times without throwing', () => {
-            const store = new UnifiedFontStore({ limit: 10 });
-            store.destroy();
-
-            expect(() => {
-                store.destroy();
-            }).not.toThrow();
-        });
-    });
-});

src/entities/Font/model/store/unifiedFontStore/unifiedFontStore.svelte.ts

@@ -1,427 +0,0 @@
-/**
- * Unified font store
- *
- * Single source of truth for font data, powered by the proxy API.
- * Extends BaseFontStore for TanStack Query integration and reactivity.
- *
- * Key features:
- * - Provider-agnostic (proxy API handles provider logic)
- * - Reactive to filter changes
- * - Optimistic updates via TanStack Query
- * - Pagination support
- * - Provider-specific shortcuts for common operations
- */
-
-import type { QueryObserverOptions } from '@tanstack/query-core';
-import type { ProxyFontsParams } from '../../../api';
-import { fetchProxyFonts } from '../../../api';
-import {
-    FontNetworkError,
-    FontResponseError,
-} from '../../../lib/errors/errors';
-import type { UnifiedFont } from '../../types';
-import { BaseFontStore } from '../baseFontStore/baseFontStore.svelte';
-
-/**
- * Unified font store wrapping TanStack Query with Svelte 5 runes
- *
- * Extends BaseFontStore to provide:
- * - Reactive state management
- * - TanStack Query integration for caching
- * - Filter change tracking with pagination reset
- * - Pagination support
- *
- * @example
- * ```ts
- * const store = new UnifiedFontStore({
- *     provider: 'google',
- *     category: 'sans-serif',
- *     limit: 50
- * });
- *
- * // Access reactive state
- * $effect(() => {
- *     console.log(store.fonts);
- *     console.log(store.isLoading);
- *     console.log(store.pagination);
- * });
- *
- * // Update parameters
- * store.setCategories(['serif']);
- * store.nextPage();
- * ```
- */
-export class UnifiedFontStore extends BaseFontStore<ProxyFontsParams> {
-    /**
-     * Store pagination metadata separately from fonts
-     * This is a workaround for TanStack Query's type system
-     */
-    #paginationMetadata = $state<
-        {
-            total: number;
-            limit: number;
-            offset: number;
-        } | null
-    >(null);
-
-    /**
-     * Accumulated fonts from all pages (for infinite scroll)
-     */
-    #accumulatedFonts = $state<UnifiedFont[]>([]);
-
-    /**
-     * Pagination metadata (derived from proxy API response)
-     */
-    readonly pagination = $derived.by(() => {
-        if (this.#paginationMetadata) {
-            const { total, limit, offset } = this.#paginationMetadata;
-            return {
-                total,
-                limit,
-                offset,
-                hasMore: offset + limit < total,
-                page: Math.floor(offset / limit) + 1,
-                totalPages: Math.ceil(total / limit),
-            };
-        }
-        return {
-            total: 0,
-            limit: this.params.limit || 50,
-            offset: this.params.offset || 0,
-            hasMore: false,
-            page: 1,
-            totalPages: 0,
-        };
-    });
-
-    /**
-     * Track previous filter params to detect changes and reset pagination
-     */
-    #previousFilterParams = $state<string | null>(null);
-
-    /**
-     * Cleanup function for the filter tracking effect
-     */
-    #filterCleanup: (() => void) | null = null;
-
-    constructor(initialParams: ProxyFontsParams = {}) {
-        super(initialParams);
-
-        // Track filter params (excluding pagination params)
-        // Wrapped in $effect.root() to prevent effect_orphan error
-        this.#filterCleanup = $effect.root(() => {
-            $effect(() => {
-                const filterParams = JSON.stringify({
-                    providers: this.params.providers,
-                    categories: this.params.categories,
-                    subsets: this.params.subsets,
-                    q: this.params.q,
-                });
-
-                // If filters changed, reset offset and invalidate cache
-                if (filterParams !== this.#previousFilterParams) {
-                    if (this.#previousFilterParams) {
-                        if (this.params.offset !== 0) {
-                            this.setParams({ offset: 0 });
-                        }
-                        this.#accumulatedFonts = [];
-                        this.invalidate();
-                    }
-                    this.#previousFilterParams = filterParams;
-                }
-            });
-
-            // Effect: Sync state from Query result (Handles Cache Hits)
-            $effect(() => {
-                const data = this.result.data;
-                const offset = this.params.offset ?? 0;
-
-                // When we have data and we are at the start (offset 0),
-                // we must ensure accumulatedFonts matches the fresh (or cached) data.
-                // This fixes the issue where cache hits skip fetchFn side-effects.
-                // Only sync at offset 0 to avoid clearing fonts during cache hits at other offsets.
-                if (offset === 0 && data && data.length > 0) {
-                    this.#accumulatedFonts = data;
-                }
-            });
-        });
-    }
-
-    /**
-     * Clean up both parent and child effects
-     */
-    destroy() {
-        // Call parent cleanup (TanStack observer effect)
-        super.destroy();
-
-        // Call filter tracking effect cleanup
-        if (this.#filterCleanup) {
-            this.#filterCleanup();
-            this.#filterCleanup = null;
-        }
-    }
-
-    /**
-     * Query key for TanStack Query caching
-     * Normalizes params to treat empty arrays/strings as undefined
-     */
-    protected getQueryKey(params: ProxyFontsParams) {
-        // Normalize params to treat empty arrays/strings as undefined
-        const normalized = Object.entries(params).reduce((acc, [key, value]) => {
-            if (value === '' || value === undefined || (Array.isArray(value) && value.length === 0)) {
-                return acc;
-            }
-            return { ...acc, [key]: value };
-        }, {});
-
-        // Return a consistent key
-        return ['unifiedFonts', normalized] as const;
-    }
-
-    protected getOptions(params = this.params): QueryObserverOptions<UnifiedFont[], Error> {
-        const hasFilters = !!(params.q || params.providers || params.categories || params.subsets);
-        return {
-            queryKey: this.getQueryKey(params),
-            queryFn: () => this.fetchFn(params),
-            staleTime: hasFilters ? 0 : 5 * 60 * 1000,
-            gcTime: 10 * 60 * 1000,
-        };
-    }
-
-    /**
-     * Fetch function that calls the proxy API
-     * Returns the full response including pagination metadata
-     */
-    protected async fetchFn(params: ProxyFontsParams): Promise<UnifiedFont[]> {
-        let response: Awaited<ReturnType<typeof fetchProxyFonts>>;
-        try {
-            response = await fetchProxyFonts(params);
-        } catch (cause) {
-            throw new FontNetworkError(cause);
-        }
-
-        if (!response) {
-            throw new FontResponseError('response', response);
-        }
-        if (!response.fonts) {
-            throw new FontResponseError('response.fonts', response.fonts);
-        }
-        if (!Array.isArray(response.fonts)) {
-            throw new FontResponseError('response.fonts', response.fonts);
-        }
-
-        this.#paginationMetadata = {
-            total: response.total ?? 0,
-            limit: response.limit ?? this.params.limit ?? 50,
-            offset: response.offset ?? this.params.offset ?? 0,
-        };
-
-        const offset = params.offset ?? 0;
-        if (offset === 0) {
-            // Replace accumulated fonts on offset-0 fetch
-            this.#accumulatedFonts = response.fonts;
-        } else {
-            // Append fonts when fetching at offset > 0
-            this.#accumulatedFonts = [...this.#accumulatedFonts, ...response.fonts];
-        }
-
-        return response.fonts;
-    }
-
-    /**
-     * Get all accumulated fonts (for infinite scroll)
-     */
-    get fonts(): UnifiedFont[] {
-        return this.#accumulatedFonts;
-    }
-
-    /**
-     * Check if loading initial data
-     */
-    get isLoading(): boolean {
-        return this.result.isLoading;
-    }
-
-    /**
-     * Check if fetching (including background refetches)
-     */
-    get isFetching(): boolean {
-        return this.result.isFetching;
-    }
-
-    /**
-     * Check if error occurred
-     */
-    get isError(): boolean {
-        return this.result.isError;
-    }
-
-    /**
-     * Check if result is empty (not loading and no fonts)
-     */
-    get isEmpty(): boolean {
-        return !this.isLoading && this.fonts.length === 0;
-    }
-
-    /**
-     * Check if filter params changed and reset if needed
-     * Manually called in setParams to handle test contexts where $effect doesn't run
-     */
-    #checkAndResetFilters(newParams: Partial<ProxyFontsParams>) {
-        // Only check filter-related params (not offset/limit/page)
-        const isFilterChange = 'q' in newParams || 'providers' in newParams || 'categories' in newParams
-            || 'subsets' in newParams;
-
-        if (!isFilterChange) {
-            return;
-        }
-
-        const filterParams = JSON.stringify({
-            providers: this.params.providers,
-            categories: this.params.categories,
-            subsets: this.params.subsets,
-            q: this.params.q,
-        });
-
-        if (filterParams !== this.#previousFilterParams) {
-            // Reset offset if filter params changed
-            if (this.params.offset !== 0) {
-                // Update internal params directly to avoid recursion
-                this.updateInternalParams({ offset: 0 });
-            }
-
-            // Clear fonts if there are accumulated fonts
-            // (to avoid clearing on initial setup when no fonts exist)
-            if (this.#accumulatedFonts.length > 0) {
-                this.#accumulatedFonts = [];
-                // Clear the result to prevent effect from using stale cached data
-                this.result.data = undefined;
-            }
-
-            this.invalidate();
-            this.#previousFilterParams = filterParams;
-        }
-    }
-
-    /**
-     * Override setParams to check for filter changes
-     * @param newParams - Partial params to merge with existing
-     */
-    setParams(newParams: Partial<ProxyFontsParams>) {
-        // First update params normally
-        super.setParams(newParams);
-        // Then check if filters changed (for test contexts)
-        this.#checkAndResetFilters(newParams);
-    }
-
-    /**
-     * Set providers filter
-     */
-    setProviders(providers: ProxyFontsParams['providers']) {
-        this.setParams({ providers });
-    }
-
-    /**
-     * Set categories filter
-     */
-    setCategories(categories: ProxyFontsParams['categories']) {
-        this.setParams({ categories });
-    }
-
-    /**
-     * Set subsets filter
-     */
-    setSubsets(subsets: ProxyFontsParams['subsets']) {
-        this.setParams({ subsets });
-    }
-
-    /**
-     * Set search query
-     */
-    setSearch(search: string) {
-        this.setParams({ q: search || undefined });
-    }
-
-    /**
-     * Set sort order
-     */
-    setSort(sort: ProxyFontsParams['sort']) {
-        this.setParams({ sort });
-    }
-
-    /**
-     * Go to next page
-     */
-    nextPage() {
-        if (this.pagination.hasMore) {
-            this.setParams({
-                offset: this.pagination.offset + this.pagination.limit,
-            });
-        }
-    }
-
-    /**
-     * Go to previous page
-     */
-    prevPage() {
-        if (this.pagination.page > 1) {
-            this.setParams({
-                offset: this.pagination.offset - this.pagination.limit,
-            });
-        }
-    }
-
-    /**
-     * Go to specific page
-     */
-    goToPage(page: number) {
-        if (page >= 1 && page <= this.pagination.totalPages) {
-            this.setParams({
-                offset: (page - 1) * this.pagination.limit,
-            });
-        }
-    }
-
-    /**
-     * Set limit (items per page)
-     */
-    setLimit(limit: number) {
-        this.setParams({ limit });
-    }
-
-    get sansSerifFonts() {
-        return this.fonts.filter(f => f.category === 'sans-serif');
-    }
-
-    get serifFonts() {
-        return this.fonts.filter(f => f.category === 'serif');
-    }
-
-    get displayFonts() {
-        return this.fonts.filter(f => f.category === 'display');
-    }
-
-    get handwritingFonts() {
-        return this.fonts.filter(f => f.category === 'handwriting');
-    }
-
-    get monospaceFonts() {
-        return this.fonts.filter(f => f.category === 'monospace');
-    }
-}
-
-/**
- * Factory function to create unified font store
- */
-export function createUnifiedFontStore(params: ProxyFontsParams = {}) {
-    return new UnifiedFontStore(params);
-}
-
-/**
- * Singleton instance for global use
- * Initialized with a default limit to prevent fetching all fonts at once
- */
-export const unifiedFontStore = new UnifiedFontStore({
-    limit: 50,
-    offset: 0,
-});

src/entities/Font/ui/FontVirtualList/FontVirtualList.svelte

@@ -18,7 +18,7 @@ import {
     type FontLoadRequestConfig,
     type UnifiedFont,
     appliedFontsManager,
-    unifiedFontStore,
+    fontStore,
 } from '../../model';
 
 interface Props extends
@@ -50,7 +50,7 @@ let {
 }: Props = $props();
 
 const isLoading = $derived(
-    unifiedFontStore.isFetching || unifiedFontStore.isLoading,
+    fontStore.isFetching || fontStore.isLoading,
 );
 
 function handleInternalVisibleChange(visibleItems: UnifiedFont[]) {
@@ -82,12 +82,12 @@ function handleInternalVisibleChange(visibleItems: UnifiedFont[]) {
  */
 function loadMore() {
     if (
-        !unifiedFontStore.pagination.hasMore
-        || unifiedFontStore.isFetching
+        !fontStore.pagination.hasMore
+        || fontStore.isFetching
     ) {
         return;
     }
-    unifiedFontStore.nextPage();
+    fontStore.nextPage();
 }
 
 /**
@@ -97,17 +97,17 @@ function loadMore() {
  * of the loaded items. Only fetches if there are more pages available.
  */
 function handleNearBottom(_lastVisibleIndex: number) {
-    const { hasMore } = unifiedFontStore.pagination;
+    const { hasMore } = fontStore.pagination;
 
     // VirtualList already checks if we're near the bottom of loaded items
-    if (hasMore && !unifiedFontStore.isFetching) {
+    if (hasMore && !fontStore.isFetching) {
         loadMore();
     }
 }
 </script>
 
 <div class="relative w-full h-full">
-    {#if skeleton && isLoading && unifiedFontStore.fonts.length === 0}
+    {#if skeleton && isLoading && fontStore.fonts.length === 0}
         <!-- Show skeleton only on initial load when no fonts are loaded yet -->
         <div transition:fade={{ duration: 300 }}>
             {@render skeleton()}
@@ -115,8 +115,8 @@ function handleNearBottom(_lastVisibleIndex: number) {
     {:else}
         <!-- VirtualList persists during pagination - no destruction/recreation -->
         <VirtualList
-            items={unifiedFontStore.fonts}
-            total={unifiedFontStore.pagination.total}
+            items={fontStore.fonts}
+            total={fontStore.pagination.total}
             isLoading={isLoading}
             onVisibleItemsChange={handleInternalVisibleChange}
             onNearBottom={handleNearBottom}

src/features/GetFonts/ui/FiltersControl/FilterControls.svelte

@@ -4,7 +4,7 @@
     Sits below the filter list, separated by a top border.
 -->
 <script lang="ts">
-import { unifiedFontStore } from '$entities/Font';
+import { fontStore } from '$entities/Font';
 import type { ResponsiveManager } from '$shared/lib';
 import { cn } from '$shared/shadcn/utils/shadcn-utils';
 import { Button } from '$shared/ui';
@@ -33,7 +33,7 @@ const {
 
 $effect(() => {
     const apiSort = sortStore.apiValue;
-    untrack(() => unifiedFontStore.setSort(apiSort));
+    untrack(() => fontStore.setSort(apiSort));
 });
 
 const responsive = getContext<ResponsiveManager>('responsive');

src/widgets/ComparisonView/model/stores/comparisonStore.svelte.ts

@@ -16,7 +16,7 @@
 import {
     type UnifiedFont,
     fetchFontsByIds,
-    unifiedFontStore,
+    fontStore,
 } from '$entities/Font';
 import {
     DEFAULT_TYPOGRAPHY_CONTROLS_DATA,
@@ -85,7 +85,7 @@ export class ComparisonStore {
                 }
 
                 // Check if fonts are available to set as defaults
-                const fonts = unifiedFontStore.fonts;
+                const fonts = fontStore.fonts;
                 if (fonts.length >= 2) {
                     // Only set if we really have nothing (fallback)
                     if (!this.#fontA) this.#fontA = fonts[0];

src/widgets/ComparisonView/model/stores/comparisonStore.test.ts

@@ -4,7 +4,7 @@
  * Tests the font comparison store functionality including:
  * - Font loading via CSS Font Loading API
  * - Storage synchronization when fonts change
- * - Default values from unifiedFontStore
+ * - Default values from fontStore
  * - Reset functionality
  * - isReady computed state
  */
@@ -25,7 +25,7 @@ import {
 // Mock all dependencies
 vi.mock('$entities/Font', () => ({
     fetchFontsByIds: vi.fn(),
-    unifiedFontStore: { fonts: [] },
+    fontStore: { fonts: [] },
 }));
 
 vi.mock('$features/SetupFont', () => ({
@@ -119,7 +119,7 @@ vi.mock('$shared/lib/helpers/createPersistentStore/createPersistentStore.svelte'
 // Import after mocks
 import {
     fetchFontsByIds,
-    unifiedFontStore,
+    fontStore,
 } from '$entities/Font';
 import { createTypographyControlManager } from '$features/SetupFont';
 import { ComparisonStore } from './comparisonStore.svelte';
@@ -150,8 +150,8 @@ describe('ComparisonStore', () => {
         };
         mockStorage._clear.mockClear();
 
-        // Setup mock unifiedFontStore
-        (unifiedFontStore as any).fonts = [];
+        // Setup mock fontStore
+        (fontStore as any).fonts = [];
 
         // Setup mock fetchFontsByIds
         vi.mocked(fetchFontsByIds).mockResolvedValue([]);
@@ -301,8 +301,8 @@ describe('ComparisonStore', () => {
         });
 
         it('should handle partial restoration when only one font is found', async () => {
-            // Ensure unifiedFontStore is empty so $effect doesn't interfere
-            (unifiedFontStore as any).fonts = [];
+            // Ensure fontStore is empty so $effect doesn't interfere
+            (fontStore as any).fonts = [];
 
             mockStorage._value.fontAId = mockFontA.id;
             mockStorage._value.fontBId = mockFontB.id;
@@ -330,7 +330,7 @@ describe('ComparisonStore', () => {
     describe('Font Loading with CSS Font Loading API', () => {
         it('should construct correct font strings for checking', async () => {
             mockFontFaceSet.check.mockReturnValue(false);
-            (unifiedFontStore as any).fonts = [mockFontA, mockFontB];
+            (fontStore as any).fonts = [mockFontA, mockFontB];
             vi.mocked(fetchFontsByIds).mockResolvedValue([mockFontA, mockFontB]);
 
             const store = new ComparisonStore();
@@ -367,7 +367,7 @@ describe('ComparisonStore', () => {
             // Mock load to fail
             mockFontFaceSet.load.mockRejectedValue(new Error('Font load failed'));
 
-            (unifiedFontStore as any).fonts = [mockFontA, mockFontB];
+            (fontStore as any).fonts = [mockFontA, mockFontB];
             vi.mocked(fetchFontsByIds).mockResolvedValue([mockFontA, mockFontB]);
 
             const consoleSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
@@ -384,11 +384,11 @@ describe('ComparisonStore', () => {
         });
     });
 
-    describe('Default Values from unifiedFontStore', () => {
-        it('should set default fonts from unifiedFontStore when available', () => {
+    describe('Default Values from fontStore', () => {
+        it('should set default fonts from fontStore when available', () => {
             // Note: This test relies on Svelte 5's $effect which may not work
             // reliably in the test environment. We test the logic path instead.
-            (unifiedFontStore as any).fonts = [mockFontA, mockFontB];
+            (fontStore as any).fonts = [mockFontA, mockFontB];
 
             const store = new ComparisonStore();
 
@@ -402,9 +402,9 @@ describe('ComparisonStore', () => {
             expect(store.fontB).toBeDefined();
         });
 
-        it('should use first and last font from unifiedFontStore as defaults', () => {
+        it('should use first and last font from fontStore as defaults', () => {
             const mockFontC = UNIFIED_FONTS.lato;
-            (unifiedFontStore as any).fonts = [mockFontA, mockFontC, mockFontB];
+            (fontStore as any).fonts = [mockFontA, mockFontC, mockFontB];
 
             const store = new ComparisonStore();
 

src/widgets/FontSearch/ui/FontSearch/FontSearch.svelte

@@ -3,7 +3,7 @@
     Provides a search input and filtration for fonts
 -->
 <script lang="ts">
-import { unifiedFontStore } from '$entities/Font';
+import { fontStore } from '$entities/Font';
 import {
     FilterControls,
     Filters,
@@ -36,7 +36,7 @@ let { showFilters = $bindable(true) }: Props = $props();
 
 $effect(() => {
     const params = mapManagerToParams(filterManager);
-    untrack(() => unifiedFontStore.setParams(params));
+    untrack(() => fontStore.setParams(params));
 });
 
 const transform = new Tween(

src/widgets/SampleList/ui/SampleListSection/SampleListSection.svelte

@@ -4,7 +4,7 @@
 -->
 <script lang="ts">
 import { NavigationWrapper } from '$entities/Breadcrumb';
-import { unifiedFontStore } from '$entities/Font';
+import { fontStore } from '$entities/Font';
 import type { ResponsiveManager } from '$shared/lib';
 import { cn } from '$shared/shadcn/utils/shadcn-utils';
 import {
@@ -36,7 +36,7 @@ const responsive = getContext<ResponsiveManager>('responsive');
             id="sample_set"
             title="Sample Set"
             headerTitle="visual_output"
-            headerSubtitle="items_total: {unifiedFontStore.pagination.total ?? 0}"
+            headerSubtitle="items_total: {fontStore.pagination.total ?? 0}"
             headerAction={registerAction}
         >
             {#snippet headerContent()}