Keshi

Keshi is a tiny in-memory cache for Node and the browser that is especially suited to storing Promises (e.g. caching fetch requests).

import Keshi from 'keshi'
// or
const Keshi = require('keshi')

Usage

const cache = new Keshi()

const user = await cache.resolve(
  'user',
  () => fetch('https://myapi.com/user').then(r => r.json()),
  '5mins'
)

What this will do:

• Fetch the user from the API as it doesn't have it in cache.
• If called again within 5 minutes it will return the cached user.
• If called after 5 minutes it will fetch the user again and re-cache.

Keshi automatically cleans up expired items.

API

cache.resolve<T>(key: string, getValue: () => T | Promise<T>, expiresIn?: number | string) => Promise<T>

function getCachedUser() {
  return cache.resolve(
    'user',
    () => fetch('https://myapi.com/user').then(r => r.json()),
    '5mins' // Anything 'ms' package accepts or milliseconds as a number. Omit for no expiry.
  )
}

const user1 = await getCachedUser() // First time caches the promise and returns it
const user2 = await getCachedUser() // Second time returns the first promise if within 5mins

You can use plain values but they must still be awaited:

const plainValue = await cache.resolve('mynumber', () => 5, '10mins')
console.log(plainValue) // prints 5

cache.delete(key: string, matchStart?: boolean)

Explicitly delete a cached object.

Note: expired objects are automatically cleanup up.

If true is passed for matchStart then any cache starting with the key will be deleted:

cache.del(`project.${projectId}.`, true) // Delete all caches under this projectId

cache.clear()

Clear the whole cache.

cache.teardown()

A stale cache cleanup interval is running in the background. If your cache doesn't last the lifetime of your application then you should call teardown.