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.

``js
import { withCache } from "ultrafetch";

const enhancedFetch = withCache(fetch);
`

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

`ts
import { withCache } from "ultrafetch";

class MyCache implements Map {
clear(): void;
delete(key: K): boolean;
get(key: K): V| undefined>;
has(key: K): boolean;
set(key: K, value: V): this;
readonly size: number;
}

const 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.

`ts
import type { AsyncMap } from "ultrafetch";
import { withCache } from "ultrafetch";

class MyAsyncCache implements AsyncMap {
clear(): Promise;
delete(key: K): Promise;
get(key: K): Promise;
has(key: K): Promise;
set(key: K, value: V): Promise;
readonly size: number;
}

const enhancedFetch = withCache(fetch, { cache: new MyAsyncCache() });
`

$3

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

`ts
import { withCache, isCached } from "ultrafetch";

const enhancedFetch = withCache(fetch);
const responseA = await enhancedFetch('https://example.com');
isCached(responseA) // false
const responseB = await enhancedFetch('https://example.com');
isCached(responseB) // true
``