remember-promise

A simple utility to remember promises that were made! It is greatly inspired by the p-memoize utility but with additional built-in features and changes such as:

stale-while-revalidate behavior
ttl expiry
optimal probabilistic cache stampede prevention
ability to ignore results from being cached
zero dependencies, commonjs and guaranteed browser support!

Installation

yarn:

yarn add remember-promise

npm:

npm install remember-promise

pnpm:

pnpm install remember-promise

Usage

import { rememberPromise } from 'remember-promise';

const getAllRedditFeed = rememberPromise(() =>
  fetch('https://www.reddit.com/r/all.json').then(res => res.json())
);

const firstResult = await getAllRedditFeed();
const secondResult = await getAllRedditFeed(); // this call is cached

Options

Name	Description
`ttl`	Configures how long in milliseconds the cached result should be used before needing to be revalidated. NOTE: the actual revalidation of the cached result is done slightly before expiry by default. This can be adjusted using the `xfetchBeta` option. By default, the cached result will be used indefinitely.
`allowStale`	This enables stale-while-revalidate behavior where an expired result can still be used while waiting for it to be updated in the background asynchronously. By default, this behavior is enabled.
`cache`	This is where cached results will be stored. It can be anything you want such as lru-cache or a redis backed cache as long as it implements a `get` and `set` method. By default, this is an instance of Map.
`getCacheKey`	Identical behavior to the `cacheKey` option in p-memoize. It should return what the cache key based on the parameters of given promise function. By default, this will serialize all arguments using `JSON.stringify`.
`shouldIgnoreResult`	Determines whether the returned result should be added to the cache. By default, this is `undefined` meaning it will always use the returned result for caching.
`xfetchBeta`	This is the beta value used in optimal probabilistic cache stampede prevention where values more than 1 favors earlier revalidation while values less than 1 favors later revalidation. By default, this is set to 1 so revalidation of a cached result will happen at a random time slightly before expiry. If you wish to opt-out of this behavior, then set this value to 0.