cached-fetch
What is it?
It's a small library to cache and dedupe calls, with server rendering in mind.
How does it work?
import fetch from '@e1himself/cached-fetch'
await fetch('do as usual')
Overriding global fetch
import '@e1himself/cached-fetch/register'
await fetch('do as usual')
Integration with Astro
import { defineConfig } from 'astro/config';
import cachedFetch from '@e1himself/cached-fetch/astro';
export default defineConfig({
integrations: [
cachedFetch(),
]
});
What does it do?
The extended api is:
import { createCachedFetch, createDedupedFetch } from '@e1himself/cached-fetch'
const fetch = createDedupedFetch(
createCachedFetch(global.fetch)
)
createDedupedFetch
This will create a in memory storage which will hold the fetch promises until they are settled. If many fetch calls are made to the same resources, only the 1st one will be returned.
createCachedFetch
This is an implementation of the cache policy for server side. The spec is defined at https://developer.mozilla.org/en-US/docs/Web/API/Request/cache and each of the policy should be as close as possible from the original definition.
Customisation and further
getCacheKey
Both functions are using a similar getCacheKey(...args: Parameters<typeof fetch>): string | false
function which will be used to compute a cache key for a given request. If cache is not applicable, we should return false
, a string
otherwise.
This function can be replaced in the options object of both createCachedFetch
and createDedupedFetch
.
cache object
For introspection and cache manipulation, both of the function can receive an optional cache
object which abide to the Store<T>
interface, passed in the options object as well.
CachePolicy
For decomposition and flexibility, implementation of each of the RequestCache
value is made as an individual function. You can pass/customize each up to your liking by passing a policies
object by yourself in the createCachedFetch
options. The function signature will need to implement the CachePolicy
type.