ocache

ocache

Usage

Caching Functions

Wrap any function with defineCachedFunction to add caching with TTL, stale-while-revalidate, and request deduplication:

import { defineCachedFunction } from "ocache";

const cachedFetch = defineCachedFunction(
  async (url: string) => {
    const res = await fetch(url);
    return res.json();
  },
  {
    maxAge: 60, // Cache for 60 seconds
    name: "api-fetch",
  },
);

// First call hits the function, subsequent calls return cached result
const data = await cachedFetch("https://api.example.com/data");

Options

const cached = defineCachedFunction(fn, {
  name: "my-fn", // Cache key name (defaults to function name)
  maxAge: 10, // TTL in seconds (default: 1)
  swr: true, // Stale-while-revalidate (default: true)
  staleMaxAge: 60, // Max seconds to serve stale content
  group: "my-group", // Cache key group (default: "ocache/functions")
  getKey: (...args) => "custom-key", // Custom cache key generator
  shouldBypassCache: (...args) => false, // Skip cache entirely when true
  shouldInvalidateCache: (...args) => false, // Force refresh when true
  validate: (entry) => entry.value !== undefined, // Custom validation
  transform: (entry) => entry.value, // Transform before returning
  onError: (error) => console.error(error), // Error handler
});

Caching HTTP Handlers

Wrap HTTP handlers with defineCachedHandler for automatic response caching with etag, last-modified, and 304 Not Modified support:

import { defineCachedHandler } from "ocache";

const handler = defineCachedHandler(
  async (event) => {
    // event.req is a standard Request object
    const url = event.url ?? new URL(event.req.url);
    const data = await getExpensiveData(url.pathname);
    return new Response(JSON.stringify(data), {
      headers: { "content-type": "application/json" },
    });
  },
  {
    maxAge: 300, // Cache for 5 minutes
    swr: true,
    staleMaxAge: 600,
    varies: ["accept-language"], // Vary cache by these headers
  },
);

// Use with any server that provides Request/Response
// e.g., Bun, Deno, Cloudflare Workers, srvx, etc.

Headers-only Mode

Use headersOnly to handle conditional requests without caching the full response:

const handler = defineCachedHandler(myHandler, {
  headersOnly: true,
  maxAge: 60,
});

Custom Storage

By default, ocache uses an in-memory Map-based storage. You can provide a custom storage implementation:

import { setStorage } from "ocache";
import type { StorageInterface } from "ocache";

const redisStorage: StorageInterface = {
  get: async (key) => {
    return JSON.parse(await redis.get(key));
  },
  set: async (key, value, opts) => {
    await redis.set(key, JSON.stringify(value), opts?.ttl ? { EX: opts.ttl } : undefined);
  },
};

setStorage(redisStorage);

API

defineCachedFunction

function defineCachedFunction<T, ArgsT extends unknown[] = any[]>(
  fn: (...args: ArgsT) => T | Promise<T>,
  opts: CacheOptions<T, ArgsT> =

Wraps a function with caching support including TTL, SWR, integrity checks, and request deduplication.

Parameters:

• fn — The function to cache.
• opts — Cache configuration options.

Returns: — A new async function that returns cached results when available.

cachedFunction

const cachedFunction = defineCachedFunction;

Alias for defineCachedFunction.

defineCachedHandler

function defineCachedHandler<E extends HTTPEvent = HTTPEvent>(
  handler: EventHandler<E>,
  opts: CachedEventHandlerOptions<E> = defaultCacheOptions() as CachedEventHandlerOptions<E>,
): EventHandler<E>;

Wraps an HTTP event handler with response caching.

Automatically generates cache keys from the URL path and variable headers, sets cache-control, etag, and last-modified headers, and handles 304 Not Modified responses via conditional request headers.

Parameters:

• handler — The event handler to cache.
• opts — Cache and HTTP-specific configuration options.

Returns: — A new event handler that serves cached responses when available.

createMemoryStorage

function createMemoryStorage(): StorageInterface;

Creates an in-memory storage backed by a Map with optional TTL support (in seconds).

useStorage

function useStorage(): StorageInterface;

Returns the current storage instance. If none has been set via setStorage, lazily initializes an in-memory storage.

setStorage

function setStorage(storage: StorageInterface): void;

Sets a custom storage implementation to be used by all cached functions.

ServerRequest

interface ServerRequest extends Request

Extended Request interface with optional waitUntil for background tasks.

Compatible with srvx ServerRequest.

HTTPEvent

interface HTTPEvent

Minimal HTTP event object containing a request and an optional pre-parsed URL.

EventHandler

type EventHandler<E extends HTTPEvent = HTTPEvent> = (

Handler function that receives an HTTPEvent and returns a response value.

CacheEntry

interface CacheEntry<T = any>

Stored cache entry wrapping a cached value with metadata.

CacheOptions

interface CacheOptions<T = any, ArgsT extends unknown[] = any[]>

Options for configuring cached functions created by defineCachedFunction.

ResponseCacheEntry

interface ResponseCacheEntry

Serialized HTTP response stored in the cache by defineCachedHandler.

CacheConditions

interface CacheConditions

Conditional cache header options passed to the handleCacheHeaders hook.

CachedEventHandlerOptions

interface CachedEventHandlerOptions<
  E extends HTTPEvent = HTTPEvent,
> extends Omit<
  CacheOptions<ResponseCacheEntry, [E]>,
  "transform" | "validate"
>

Options for configuring cached HTTP handlers created by defineCachedHandler.

Extends CacheOptions (without transform and validate, which are set internally).

Development

local development

• Clone this repository
• Install latest LTS version of Node.js
• Enable Corepack using corepack enable
• Install dependencies using pnpm install
• Run interactive tests using pnpm dev

License

Published under the MIT license 💛.