DataFetcher

Defined in: packages/core/src/data/data-fetcher.ts:146

HTTP data fetcher with caching and retry support.

Remarks

Features:

• In-memory caching with TTL
• Conditional requests (If-None-Match, If-Modified-Since)
• Automatic retry with exponential backoff
• Request timeout and cancellation
• GeoJSON validation
• Lifecycle callbacks

Example

const fetcher = new DataFetcher({
  cache: { enabled: true, defaultTTL: 300000, maxSize: 100 },
  retry: { enabled: true, maxRetries: 3, initialDelay: 1000, maxDelay: 10000 },
  timeout: 30000,
});

// Fetch with caching
const result = await fetcher.fetch('https://example.com/data.geojson');
console.log(`Fetched ${result.featureCount} features in ${result.duration}ms`);

// Prefetch for later use
await fetcher.prefetch('https://example.com/data2.geojson');

// Force fresh fetch
const fresh = await fetcher.fetch(url, { skipCache: true });

Constructors

Constructor

new DataFetcher(config?): DataFetcher

Defined in: packages/core/src/data/data-fetcher.ts:175

Create a new DataFetcher instance

Parameters

Parameter	Type	Description
config?	Partial<FetcherConfig>	Fetcher configuration

Returns

DataFetcher

Methods

abortAll()

abortAll(): void

Defined in: packages/core/src/data/data-fetcher.ts:316

Abort all active requests

Returns

void

---

clearCache()

clearCache(): void

Defined in: packages/core/src/data/data-fetcher.ts:300

Clear all cached entries

Returns

void

---

fetch()

fetch(url, options?): Promise<FetchResult>

Defined in: packages/core/src/data/data-fetcher.ts:212

Fetch GeoJSON data from a URL

Parameters

Parameter	Type	Description
url	string	URL to fetch from
options	FetchOptions	Fetch options

Returns

Promise<FetchResult>

Fetch result with data and metadata

Throws

On network error, timeout, invalid JSON, or non-GeoJSON response

Example

const result = await fetcher.fetch(
  'https://example.com/data.geojson',
  {
    ttl: 60000, // 1 minute cache
    onRetry: (attempt, delay, error) => {
      console.log(`Retry ${attempt} in ${delay}ms: ${error.message}`);
    },
  }
);

---

getCacheStats()

getCacheStats(): CacheStats

Defined in: packages/core/src/data/data-fetcher.ts:309

Get cache statistics

Returns

CacheStats

Cache stats including size, hits, misses, and hit rate

---

invalidate()

invalidate(url): void

Defined in: packages/core/src/data/data-fetcher.ts:293

Invalidate cached entry for a URL

Parameters

Parameter	Type	Description
url	string	URL to invalidate

Returns

void

Example

// Force next fetch to get fresh data
fetcher.invalidate('https://example.com/data.geojson');

---

prefetch()

prefetch(url, ttl?): Promise<void>

Defined in: packages/core/src/data/data-fetcher.ts:278

Prefetch data and store in cache

Parameters

Parameter	Type	Description
url	string	URL to prefetch
ttl?	number	Optional custom TTL for cached entry

Returns

Promise<void>

Remarks

Useful for preloading data that will be needed soon. Does not return the data.

Example

// Prefetch data for quick access later
await fetcher.prefetch('https://example.com/data.geojson', 600000);