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.

import { withCache } from "ultrafetch";

const enhancedFetch = withCache(fetch);

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

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.

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

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

const 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.

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