[](https://www.npmjs.org/package/cache-point)
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[](https://www.npmjs.org/package/cache-point)
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[](https://travis-ci.org/75lb/cache-point)
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[](https://david-dm.org/75lb/cache-point)
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[](https://github.com/feross/standard)
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# cache-point
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Simple, filesystem-backed memoisation cache. Use to cache the output of expensive operations speeding up future invocations with the same input.
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## Synopsis
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```js
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const Cache = require('cache-point')
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/* a mock function to simulate a slow remote request */
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async function fetchUser (id) {
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return new Promise(resolve => {
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setTimeout(() => {
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resolve({ id, name: 'Layla' })
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}, 1000)
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})
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}
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class Users {
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constructor () {
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this.cache = new Cache({ dir: 'tmp/example' })
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}
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async getUser (id) {
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let user
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try {
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/* cache.read() will resolve on hit, reject on miss */
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user = await this.cache.read(id)
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} catch (err) {
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if (err.code === 'ENOENT') {
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/* cache miss, fetch remote user */
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user = await fetchUser(id)
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this.cache.write(id, user)
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}
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}
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return user
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}
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}
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async function start () {
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console.time('getUser')
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const users = new Users()
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const user = await users.getUser(1)
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console.timeEnd('getUser')
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console.log(user)
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}
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start().catch(console.error)
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```
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The first invocation will take 1 second while the remote user is fetched.
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```
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$ node example/simple.js
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getUser: 1.025s
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{ id: 10, name: 'Layla' }
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```
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Since the cache is now warm, future invocations will be fast.
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```
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$ node example/simple.js
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getUser: 17.07ms
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{ id: 10, name: 'Layla' }
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```
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## API Reference
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{{>main}}
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* * *
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© 2016-20 Lloyd Brookes \<75pound@gmail.com\>.
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Tested by [test-runner](https://github.com/test-runner-js/test-runner). Documented by [jsdoc-to-markdown](https://github.com/jsdoc2md/jsdoc-to-markdown).
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