ultrafetch

Modular utilities for enhancing fetch behavior. Bring Your Own Fetch implementation supports both node-fetch and unidici's fetch (globally available in node@18+).

withCache

The withCache function enhances fetch with RFC-7234 compliant cache behavior. The default cache is a simple in-memory Map, but custom caches are also supported.

1import { withCache } from "ultrafetch";
2
3const enhancedFetch = withCache(fetch);

Any custom cache that adheres to a Map interface is valid.

1import { withCache } from "ultrafetch";
2
3class MyCache implements Map {
4  clear(): void;
5  delete(key: K): boolean;
6  get(key: K): V| undefined>;
7  has(key: K): boolean;
8  set(key: K, value: V): this;
9  readonly size: number;
10}
11
12const enhancedFetch = withCache(fetch, { cache: new MyCache() });

Custom caches can also use the AsyncMap interface, which is the same as a standard Map but each method is async.

1import type { AsyncMap } from "ultrafetch";
2import { withCache } from "ultrafetch";
3
4class MyAsyncCache implements AsyncMap {
5  clear(): Promise<void>;
6  delete(key: K): Promise<boolean>;
7  get(key: K): Promise<V | undefined>;
8  has(key: K): Promise<boolean>;
9  set(key: K, value: V): Promise<this>;
10  readonly size: number;
11}
12
13const enhancedFetch = withCache(fetch, { cache: new MyAsyncCache() });

isCached

The isCached export can be used to determine if a given Response was returned from the cache or not.

1import { withCache, isCached } from "ultrafetch";
2
3const enhancedFetch = withCache(fetch);
4const responseA = await enhancedFetch('https://example.com');
5isCached(responseA) // false
6const responseB = await enhancedFetch('https://example.com');
7isCached(responseB) // true