Package Exports

cache-point

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (cache-point) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

cache-point

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

Synopsis

const Cache = require('cache-point')

/* a mock function to simulate a slow remote request */
async function fetchUser (id) {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve({ id, name: 'Layla' })
    }, 1000)
  })
}

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
  }
}

async function start () {
  console.time('getUser')
  const users = new Users()
  const user = await users.getUser(1)
  console.timeEnd('getUser')
  console.log(user)
}

start().catch(console.error)

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])
  - .dir : string
  - .read(keys) ⇒ Promise
  - .readSync(keys) ⇒ string
  - .write(keys, content) ⇒ Promise
  - .writeSync(keys, content)
  - .getChecksum(keys) ⇒ string
  - .clear() ⇒ Promise
  - .remove() ⇒ Promise

Cache ⏏

Kind: Exported class

new Cache([options])

Param	Type
[options]	`object`
[options.dir]	`string`

cache.dir : `string`

Current cache directory. Can be changed at any time.

Kind: instance property of Cache

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.