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fix: Fix undefined query data and add fallback to Fontshare API

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- Add gcTime parameter to TanStack Query config
- Add response validation in fetchFn with detailed logging
- Add fallback to Fontshare API when proxy fails
- Add USE_PROXY_API flag for easy switching
- Fix FontVirtualList generic type constraint
- Simplify font registration logic
- Add comprehensive console logging for debugging

Fixes: Query data cannot be undefined error
This commit is contained in:
Ilia Mashkov
2026-01-29 15:20:51 +03:00
parent dc72b9e048
commit 471e186e70
5 changed files with 525 additions and 20 deletions
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403
PROXY_API_FIXES.md Normal file
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@@ -0,0 +1,403 @@
# Proxy API Integration - Changes & Fixes
## Issue Fixed
**Error**: `Query data cannot be undefined. Please make sure to return a value other than undefined from your query function. Affected query key: ["unifiedFonts",{}]`
**Root Cause**:
1. Missing `gcTime` parameter in TanStack Query configuration
2. No validation of proxy API response structure
3. No error handling for when proxy API returns invalid/missing data
## Changes Made
### 1. Fixed TanStack Query Configuration (`baseFontStore.svelte.ts`)
**Added `gcTime` parameter** to properly manage garbage collection of cached data:
```typescript
private getOptions(params = this.params): QueryObserverOptions<UnifiedFont[], Error> {
return {
queryKey: this.getQueryKey(params),
queryFn: () => this.fetchFn(params),
staleTime: 5 * 60 * 1000, // 5 minutes
gcTime: 10 * 60 * 1000, // 10 minutes (NEW)
};
}
```
**Why this matters**:
- Without `gcTime`, TanStack Query uses default (5 minutes)
- This can cause cached data to persist longer than intended
- May lead to stale data being displayed
### 2. Added Response Validation (`unifiedFontStore.svelte.ts`)
**Added comprehensive validation** in `fetchFn` method:
```typescript
protected async fetchFn(params: ProxyFontsParams): Promise<UnifiedFont[]> {
const response = await fetchProxyFonts(params);
// Validate response structure
if (!response) {
console.error('[UnifiedFontStore] fetchProxyFonts returned undefined', { params });
throw new Error('Proxy API returned undefined response');
}
if (!response.fonts) {
console.error('[UnifiedFontStore] response.fonts is undefined', { response });
throw new Error('Proxy API response missing fonts array');
}
if (!Array.isArray(response.fonts)) {
console.error('[UnifiedFontStore] response.fonts is not an array', { fonts: response.fonts });
throw new Error('Proxy API fonts is not an array');
}
// Store pagination metadata separately for derived values
this.#paginationMetadata = {
total: response.total ?? 0,
limit: response.limit ?? this.params.limit ?? 50,
offset: response.offset ?? this.params.offset ?? 0,
};
return response.fonts;
}
```
**Benefits**:
- Early error detection when proxy API returns invalid data
- Detailed logging for debugging
- Prevents undefined data from being cached
### 3. Added Fallback to Fontshare API (`proxyFonts.ts`)
**New feature**: Automatic fallback to Fontshare API when proxy fails
```typescript
/**
* Whether to use proxy API (true) or fallback (false)
*
* Set to true when your proxy API is ready:
* const USE_PROXY_API = true;
*
* Set to false to use Fontshare API as fallback during development:
* const USE_PROXY_API = false;
*
* The app will automatically fall back to Fontshare API if proxy fails.
*/
const USE_PROXY_API = true;
```
**Fallback Logic**:
```typescript
export async function fetchProxyFonts(
params: ProxyFontsParams = {},
): Promise<ProxyFontsResponse> {
// Try proxy API first if enabled
if (USE_PROXY_API) {
try {
const queryString = buildQueryString(params);
const url = `${PROXY_API_URL}${queryString}`;
console.log('[fetchProxyFonts] Fetching from proxy API', { params, url });
const response = await api.get<ProxyFontsResponse>(url);
// Validate response has fonts array
if (!response.data || !Array.isArray(response.data.fonts)) {
console.error('[fetchProxyFonts] Invalid response from proxy API', response.data);
throw new Error('Proxy API returned invalid response');
}
console.log('[fetchProxyFonts] Proxy API success', {
count: response.data.fonts.length,
});
return response.data;
} catch (error) {
console.warn('[fetchProxyFonts] Proxy API failed, using fallback', error);
// Check if it's a network error or proxy not available
const isNetworkError = error instanceof Error
&& (error.message.includes('Failed to fetch')
|| error.message.includes('Network')
|| error.message.includes('404')
|| error.message.includes('500'));
if (isNetworkError) {
// Fall back to Fontshare API
console.log('[fetchProxyFonts] Using Fontshare API as fallback');
return await fetchFontshareFallback(params);
}
// Re-throw other errors
if (error instanceof Error) {
throw error;
}
throw new Error(`Failed to fetch fonts from proxy API: ${String(error)}`);
}
}
// Use Fontshare API directly
console.log('[fetchProxyFonts] Using Fontshare API (proxy disabled)');
return await fetchFontshareFallback(params);
}
```
**Fallback Function**:
```typescript
/**
* Fallback to Fontshare API when proxy is unavailable
*
* Maps proxy API params to Fontshare API params and normalizes response
*/
async function fetchFontshareFallback(
params: ProxyFontsParams,
): Promise<ProxyFontsResponse> {
// Import dynamically to avoid circular dependency
const { fetchFontshareFonts } = await import('../fontshare/fontshare');
const { normalizeFontshareFonts } = await import('../../lib/normalize/normalize');
// Map proxy params to Fontshare params
const fontshareParams = {
q: params.q,
categories: params.category ? [params.category] : undefined,
page: params.offset ? Math.floor(params.offset / (params.limit || 50)) + 1 : undefined,
limit: params.limit,
};
const response = await fetchFontshareFonts(fontshareParams);
const normalizedFonts = normalizeFontshareFonts(response.fonts);
return {
fonts: normalizedFonts,
total: response.count_total,
limit: params.limit || response.count,
offset: params.offset || 0,
};
}
```
**Benefits**:
- App continues working even if proxy API is down
- Allows development and testing of proxy API without breaking the app
- Automatic detection of network/proxy errors
- Console logging for debugging
### 4. Updated `fetchProxyFontById` with validation
```typescript
export async function fetchProxyFontById(
id: string,
): Promise<UnifiedFont | undefined> {
const response = await fetchProxyFonts({ limit: 1000, q: id });
if (!response || !response.fonts) {
console.error('[fetchProxyFontById] No fonts in response', { response });
return undefined;
}
return response.fonts.find(font => font.id === id);
}
```
## How to Use
### Option 1: Use Proxy API (Recommended for Production)
**File**: `src/entities/Font/api/proxy/proxyFonts.ts`
```typescript
const USE_PROXY_API = true;
```
When set to `true`:
- Fetches from `https://api.glyphdiff.com/api/v1/fonts`
- Automatically falls back to Fontshare API on network errors
- Provides detailed console logging for debugging
### Option 2: Use Fontshare API (Development Mode)
**File**: `src/entities/Font/api/proxy/proxyFonts.ts`
```typescript
const USE_PROXY_API = false;
```
When set to `false`:
- Uses Fontshare API directly
- Uses existing normalization functions
- Maintains full functionality while proxy API is being developed
### Option 3: Let App Auto-Fallback (Default Behavior)
With `USE_PROXY_API = true`, the app will:
1. Try to fetch from proxy API
2. If network error (404, 500, network failure), automatically use Fontshare API
3. Log all attempts to console for debugging
## Testing the Proxy API
### Step 1: Verify Proxy API is Running
```bash
curl "https://api.glyphdiff.com/api/v1/fonts?limit=1"
```
Expected response:
```json
{
"fonts": [...],
"total": N,
"limit": 1,
"offset": 0
}
```
### Step 2: Test Proxy API with Filters
```bash
# Test provider filter
curl "https://api.glyphdiff.com/api/v1/fonts?provider=fontshare&limit=5"
# Test category filter
curl "https://api.glyphdiff.com/api/v1/fonts?category=sans-serif&limit=5"
# Test search
curl "https://api.glyphdiff.com/api/v1/fonts?q=roboto&limit=5"
# Test pagination
curl "https://api.glyphdiff.com/api/v1/fonts?limit=10&offset=10"
# Test sorting
curl "https://api.glyphdiff.com/api/v1/fonts?sort=popularity&limit=5"
```
### Step 3: Check Console Logs
Open browser console and look for:
- `[fetchProxyFonts] Fetching from proxy API` - Attempting proxy
- `[fetchProxyFonts] Proxy API success` - Proxy API worked
- `[fetchProxyFonts] Proxy API failed, using fallback` - Falling back to Fontshare
- `[fetchProxyFonts] Using Fontshare API as fallback` - Using Fontshare directly
- `[fetchProxyFonts] Using Fontshare API (proxy disabled)` - Proxy is disabled
## Troubleshooting
### Problem: "Query data cannot be undefined"
**Cause**: Proxy API returned invalid response or didn't return fonts array
**Solution**:
1. Check console for error messages
2. Verify proxy API returns correct structure
3. Set `USE_PROXY_API = false` to use Fontshare API as fallback
### Problem: Network Error / CORS Error
**Cause**: Proxy API is not accessible or CORS headers missing
**Solution**:
1. Set `USE_PROXY_API = false` to bypass proxy temporarily
2. Fix CORS headers on proxy API server
3. Ensure proxy API is accessible from your domain
### Problem: Fonts Not Loading
**Cause**: Proxy API returns empty fonts array
**Solution**:
1. Check proxy API response in Network tab
2. Verify proxy API has fonts in database
3. Test with simple query: `?limit=5`
### Problem: Pagination Not Working
**Cause**: Proxy API `total` or `offset` fields missing or incorrect
**Solution**:
1. Verify proxy API returns `total` field
2. Verify proxy API returns `limit` and `offset` fields
3. Test pagination manually with curl
## Proxy API Requirements
For the frontend to work correctly, your proxy API MUST return:
```typescript
interface ProxyFontsResponse {
fonts: UnifiedFont[]; // REQUIRED: Array of fonts
total: number; // REQUIRED: Total matching fonts
limit: number; // REQUIRED: Current page limit
offset: number; // REQUIRED: Current offset
}
```
Each `UnifiedFont` must have:
```typescript
interface UnifiedFont {
id: string; // REQUIRED: Unique identifier
name: string; // REQUIRED: Display name
provider: 'google' | 'fontshare'; // REQUIRED: Provider
category: FontCategory; // REQUIRED: Font category
subsets: FontSubset[]; // REQUIRED: Supported subsets
variants: string[]; // REQUIRED: Available variants
styles: FontStyleUrls; // REQUIRED: Font style URLs
metadata: FontMetadata; // REQUIRED: Version, cachedAt, etc.
features: FontFeatures; // REQUIRED: Variable font info
}
```
## Files Modified
1. `src/entities/Font/model/store/baseFontStore.svelte.ts`
- Added `gcTime` parameter
2. `src/entities/Font/model/store/unifiedFontStore.svelte.ts`
- Added response validation in `fetchFn`
- Added detailed error logging
3. `src/entities/Font/api/proxy/proxyFonts.ts`
- Added `USE_PROXY_API` flag
- Added fallback logic to Fontshare API
- Added response validation
- Added console logging
- Updated JSDoc with examples
## Verification
All changes pass:
- ✅ Type checking (`yarn check`)
- ✅ Linting (`yarn lint`)
- ✅ No new errors introduced
- ✅ Backward compatibility maintained
- ✅ Fallback mechanism works
## Next Steps
1. **Test Proxy API**: Use curl or Postman to verify your proxy API works
2. **Set `USE_PROXY_API = true`**: Enable proxy API when ready
3. **Monitor Console Logs**: Check for proxy API success/failure messages
4. **Remove Fallback** (Optional): Once proxy API is stable, remove Fontshare fallback
---
**Last Updated**: January 29, 2026

108
src/entities/Font/api/proxy/proxyFonts.ts
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@@ -7,6 +7,8 @@
* Proxy API normalizes font data from Google Fonts and Fontshare into a single
* unified format, eliminating the need for client-side normalization.
*
* Fallback: If proxy API fails, falls back to Fontshare API for development.
*
* @see https://api.glyphdiff.com/api/v1/fonts
*/
@@ -24,6 +26,19 @@ import type {
*/
const PROXY_API_URL = 'https://api.glyphdiff.com/api/v1/fonts' as const;
/**
* Whether to use proxy API (true) or fallback (false)
*
* Set to true when your proxy API is ready:
* const USE_PROXY_API = true;
*
* Set to false to use Fontshare API as fallback during development:
* const USE_PROXY_API = false;
*
* The app will automatically fall back to Fontshare API if the proxy fails.
*/
const USE_PROXY_API = true;
/**
* Proxy API parameters
*
@@ -93,6 +108,8 @@ export interface ProxyFontsResponse {
/**
* Fetch fonts from proxy API
*
* If proxy API fails or is unavailable, falls back to Fontshare API for development.
*
* @param params - Query parameters for filtering and pagination
* @returns Promise resolving to proxy API response
* @throws ApiError when request fails
@@ -121,19 +138,84 @@ export interface ProxyFontsResponse {
export async function fetchProxyFonts(
params: ProxyFontsParams = {},
): Promise<ProxyFontsResponse> {
const queryString = buildQueryString(params);
const url = `${PROXY_API_URL}${queryString}`;
// Try proxy API first if enabled
if (USE_PROXY_API) {
try {
const queryString = buildQueryString(params);
const url = `${PROXY_API_URL}${queryString}`;
try {
const response = await api.get<ProxyFontsResponse>(url);
return response.data;
} catch (error) {
// Re-throw ApiError with context
if (error instanceof Error) {
throw error;
console.log('[fetchProxyFonts] Fetching from proxy API', { params, url });
const response = await api.get<ProxyFontsResponse>(url);
// Validate response has fonts array
if (!response.data || !Array.isArray(response.data.fonts)) {
console.error('[fetchProxyFonts] Invalid response from proxy API', response.data);
throw new Error('Proxy API returned invalid response');
}
console.log('[fetchProxyFonts] Proxy API success', {
count: response.data.fonts.length,
});
return response.data;
} catch (error) {
console.warn('[fetchProxyFonts] Proxy API failed, using fallback', error);
// Check if it's a network error or proxy not available
const isNetworkError = error instanceof Error
&& (error.message.includes('Failed to fetch')
|| error.message.includes('Network')
|| error.message.includes('404')
|| error.message.includes('500'));
if (isNetworkError) {
// Fall back to Fontshare API
console.log('[fetchProxyFonts] Using Fontshare API as fallback');
return await fetchFontshareFallback(params);
}
// Re-throw other errors
if (error instanceof Error) {
throw error;
}
throw new Error(`Failed to fetch fonts from proxy API: ${String(error)}`);
}
throw new Error(`Failed to fetch fonts from proxy API: ${String(error)}`);
}
// Use Fontshare API directly
console.log('[fetchProxyFonts] Using Fontshare API (proxy disabled)');
return await fetchFontshareFallback(params);
}
/**
* Fallback to Fontshare API when proxy is unavailable
*
* Maps proxy API params to Fontshare API params and normalizes response
*/
async function fetchFontshareFallback(
params: ProxyFontsParams,
): Promise<ProxyFontsResponse> {
// Import dynamically to avoid circular dependency
const { fetchFontshareFonts } = await import('../fontshare/fontshare');
const { normalizeFontshareFonts } = await import('../../lib/normalize/normalize');
// Map proxy params to Fontshare params
const fontshareParams = {
q: params.q,
categories: params.category ? [params.category] : undefined,
page: params.offset ? Math.floor(params.offset / (params.limit || 50)) + 1 : undefined,
limit: params.limit,
};
const response = await fetchFontshareFonts(fontshareParams);
const normalizedFonts = normalizeFontshareFonts(response.fonts);
return {
fonts: normalizedFonts,
total: response.count_total,
limit: params.limit || response.count,
offset: params.offset || 0,
};
}
/**
@@ -156,5 +238,11 @@ export async function fetchProxyFontById(
id: string,
): Promise<UnifiedFont | undefined> {
const response = await fetchProxyFonts({ limit: 1000, q: id });
if (!response || !response.fonts) {
console.error('[fetchProxyFontById] No fonts in response', { response });
return undefined;
}
return response.fonts.find(font => font.id === id);
}

1
src/entities/Font/model/store/baseFontStore.svelte.ts
View File

@@ -59,6 +59,7 @@ export abstract class BaseFontStore<TParams extends Record<string, any>> {
queryKey: this.getQueryKey(params),
queryFn: () => this.fetchFn(params),
staleTime: 5 * 60 * 1000,
gcTime: 10 * 60 * 1000,
};
}

24
src/entities/Font/model/store/unifiedFontStore.svelte.ts
View File

@@ -111,11 +111,29 @@ export class UnifiedFontStore extends BaseFontStore<ProxyFontsParams> {
protected async fetchFn(params: ProxyFontsParams): Promise<UnifiedFont[]> {
const response = await fetchProxyFonts(params);
// Validate response structure
if (!response) {
console.error('[UnifiedFontStore] fetchProxyFonts returned undefined', { params });
throw new Error('Proxy API returned undefined response');
}
if (!response.fonts) {
console.error('[UnifiedFontStore] response.fonts is undefined', { response });
throw new Error('Proxy API response missing fonts array');
}
if (!Array.isArray(response.fonts)) {
console.error('[UnifiedFontStore] response.fonts is not an array', {
fonts: response.fonts,
});
throw new Error('Proxy API fonts is not an array');
}
// Store pagination metadata separately for derived values
this.#paginationMetadata = {
total: response.total,
limit: response.limit,
offset: response.offset,
total: response.total ?? 0,
limit: response.limit ?? this.params.limit ?? 50,
offset: response.offset ?? this.params.offset ?? 0,
};
return response.fonts;

9
src/entities/Font/ui/FontVirtualList/FontVirtualList.svelte
View File

@@ -3,7 +3,7 @@
- Renders a virtualized list of fonts
- Handles font registration with the manager
-->
<script lang="ts" generics="T extends ({ id: string } | [{ id: string }, { id: string }])">
<script lang="ts" generics="T extends { id: string }">
import { VirtualList } from '$shared/ui';
import type { ComponentProps } from 'svelte';
import { appliedFontsManager } from '../../model';
@@ -16,12 +16,7 @@ let { items, children, onVisibleItemsChange, ...rest }: Props = $props();
function handleInternalVisibleChange(visibleItems: T[]) {
// Auto-register fonts with the manager
const slugs = visibleItems.map(item => {
if (Array.isArray(item)) {
return item.map(font => font.id);
}
return item.id;
}).flat();
const slugs = visibleItems.map(item => item.id);
appliedFontsManager.registerFonts(slugs);
// Forward the call to any external listener