cache-point

Simple, filesystem-backed memoisation cache. Use to cache the output of expensive operations speeding up future invocations with the same input.

Synopsis

``js
import Cache from 'cache-point'
import { setTimeout as sleep } from 'node:timers/promises'

/ mock function to simulate a slow, remote request /
async function fetchUser (id) {
await sleep(1000)
return { id, name: 'Layla' }
}

class Users {
constructor () {
this.cache = new Cache({ dir: 'tmp/example' })
}

async getUser (id) {
let user
try {
/ cache.read() will resolve on hit, reject on miss /
user = await this.cache.read(id)
} catch (err) {
if (err.code === 'ENOENT') {
/ cache miss, fetch remote user /
user = await fetchUser(id)
this.cache.write(id, user)
}
}
return user
}
}

console.time('getUser')
const users = new Users()
const user = await users.getUser(10)
console.timeEnd('getUser')
console.log(user)
`

The first invocation will take 1 second while the remote user is fetched.

`
$ node example/simple.js
getUser: 1.025s
{ id: 10, name: 'Layla' }
`

Since the cache is now warm, future invocations will be fast.

`
$ node example/simple.js
getUser: 17.07ms
{ id: 10, name: 'Layla' }
`

API Reference

cache-point

* cache-point
* Cache ⏏
* [new Cache([options])](#new_module_cache-point--Cache_new)
* .dir : string
* .read(keys) ⇒ Promise
* .readSync(keys) ⇒ string
* .write(keys, content) ⇒ Promise
* .writeSync(keys, content)
* .getChecksum(keys) ⇒ string
* .clear() ⇒ Promise
* .remove() ⇒ Promise

$3

#### cache.read(keys) ⇒ Promise
A cache hit resolves with the stored value, a miss rejects with an ENOENT error code.

Kind: instance method of Cache
Throws:

- ENOENT


| Param | Type | Description |
| --- | --- | --- |
| keys | \* | One or more values to uniquely identify the data. Can be any value, or an array of values of any type. |

#### cache.readSync(keys) ⇒ string
A cache hit returns the stored value, a miss returns null`.

Kind: instance method of Cache

| Param | Type | Description |
| --- | --- | --- |
| keys | \* | One or more values to uniquely identify the data. Can be any value, or an array of values of any type. |

#### cache.write(keys, content) ⇒ Promise
Write some data to the cache. Returns a promise which resolves when the write is complete.

Kind: instance method of Cache

| Param | Type | Description |
| --- | --- | --- |
| keys | \* | One or more values to index the data, e.g. a request object or set of function args. |
| content | \* | the data to store |

#### cache.writeSync(keys, content)
Write some data to the cache with a key.

Kind: instance method of Cache

| Param | Type | Description |
| --- | --- | --- |
| keys | \* | One or more values to index the data, e.g. a request object or set of function args. |
| content | \* | the data to store |

#### cache.getChecksum(keys) ⇒ string
Used internally to convert a key value into a hex checksum. Override if for some reason you need a different hashing strategy.

Kind: instance method of Cache

| Param | Type | Description |
| --- | --- | --- |
| keys | \* | One or more values to index the data, e.g. a request object or set of function args. |

#### cache.clear() ⇒ Promise
Clears the cache. Returns a promise which resolves once the cache is clear.

Kind: instance method of Cache

#### cache.remove() ⇒ Promise
Clears and removes the cache directory. Returns a promise which resolves once the remove is complete.

Kind: instance method of Cache

*

© 2016-25 Lloyd Brookes \.

Tested by test-runner. Documented by jsdoc-to-markdown.