fetchache

library0.1.6jsnpmunverified

Cross-platform fetch wrapper that adds HTTP caching support to any fetch implementation using a key-value cache. Version 0.1.6 is the latest stable release. It follows HTTP Caching (RFC 7234) and Conditional Requests (RFC 7232) standards, allowing server-like caching behavior in non-browser environments (Node.js, workers). Unlike simple memoization, it respects Cache-Control headers, ETags, and expiration. Ships TypeScript types. Requires Node >= 16. Low release cadence; maintained by Ardatan/whatwg-node ecosystem.

storage

npm install fetchache

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · FETCHACHE

fetchache

storagejavascriptv0.1.6

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

fetchFactory

✓ import { fetchFactory } from 'fetchache'

✗ const fetchFactory = require('fetchache').fetchFactory

Package is ESM-only; CommonJS require() will fail. Use named import.

Response

✓ import { Response } from 'fetchache'

✗ import { Response } from '@whatwg-node/fetch'

fetchache re-exports Response for convenience, but you must provide your own fetch implementation.

fetchWithCache

✓ const fetchWithCache = fetchFactory({ fetch, Response, cache })

✗ const fetchWithCache = fetchFactory({ fetch, cache })

You must pass both fetch and Response constructors, not just fetch. Otherwise errors occur.

Creates a cached fetch using an in-memory Map, demonstrating the minimal setup with @whatwg-node/fetch.

import { fetchFactory } from 'fetchache'; import { fetch, Response } from '@whatwg-node/fetch'; const cache = new Map<string, string>(); const cacheImpl = { get: async (key: string) => cache.get(key) ?? undefined, set: async (key: string, value: string) => { cache.set(key, value); }, }; const fetchWithCache = fetchFactory({ fetch, Response, cache: cacheImpl }); const response = await fetchWithCache('https://jsonplaceholder.typicode.com/todos/1'); const data = await response.json(); console.log(data);

Debug

Known issues

gotchaMust provide both fetch and Response implementations; missing one causes cryptic errors.

fix

Always pass both fetch and Response. Use @whatwg-node/fetch for Node.js.

affects: >=0.1.0

gotchaCache implementation must match the expected interface: get and set with async string keys and values.

fix

Implement cache { get(key: string): Promise<string|undefined>; set(key: string, value: string): Promise<void> }.

affects: >=0.1.0

gotchaPackage is ESM-only; using require() throws 'ERR_REQUIRE_ESM'.

fix

Use import syntax or dynamic import(). Set 'type':'module' in package.json if running as CommonJS.

affects: >=0.1.0

gotchaThe cache key includes full URL and method; sensitive headers are not cached.

fix

Understand that cache keys are derived from the request; do not rely on manual key generation.

affects: >=0.1.0

Errors

Common errors & fixes

TypeError: fetch is not a constructor

Passing a native fetch or a fetch that is not a constructor (e.g., from undici or cross-fetch).

fix

Use @whatwg-node/fetch which exports a constructor-compatible fetch. Alternatively, wrap fetch using the factory pattern: const fetchFunc = (...args) => fetch(...args);

ERR_REQUIRE_ESM

Using require('fetchache') in a CommonJS file.

fix

Change to import { fetchFactory } from 'fetchache' or use dynamic import().

TypeError: cache.get is not a function

Passed cache object without implementing the get method.

fix

Ensure cache implements { get: (key: string) => Promise<string | undefined> }.

Upgrade

Version history

0.1.6latest on npm

Audit

Dependencies

@whatwg-node/fetchoptionalRecommended fetch and Response polyfill for Node.js; otherwise must provide custom fetch/Response.

Agent activity

21 hits · last 30 days

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Resources

githubhttps://github.com/ardatan/whatwg-node ↗

packagefetchache ↗

homepagehttps://github.com/ardatan/whatwg-node#readme ↗