Simple React "cache" api function. No clearing strategies e.g. LRU etc. Just simple interval clearing. Official version is currently available ONLY in react canaries and RSC environment i.e. “react-server” exports condition. Depends on object-hash package to create hash key from arguments and optional additional key.

react-cache.ts

import objectHash from "object-hash";

const cacheTimeout = 60 * 60 * 1000

let store: Record<string, unknown> = {};

export function cache<A extends unknown[], B = unknown>(
  fn: (...args: A) => Promise<B>,
  key?: string // optional key for guaranteed uniqueness
) {
  return async (...args: A) => {
    const hash = objectHash([...args, key]);
    if (hash in store) {
      return store[hash] as B;
    }
    const response = await fn(...args);
    store[hash] = response;
    return response;
  };
}

export function clear() {
  store = {};
}

setTimeout(clear, cacheTimeout);

// usage

async function fetchData() {
  const response = await fetch("http://example.com/movies.json");
  const data = await response.json();
  return data
}

cache(fetchData, "movies"); // normal request
cache(fetchData, "movies"); // no request - uses cache

I asked Dan Abramov (official React spokesman) about the cache function availability and created this snippet for anyone's benefit.