147 lines
5.6 KiB
Markdown
147 lines
5.6 KiB
Markdown
[](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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<a name="module_cache-point"></a>
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## cache-point
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A memoisation solution intended to cache the output of expensive operations, speeding up future invocations with the same input.
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**Example**
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```js
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const Cache = require('cache-point')
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const cache = new Cache({ dir: 'tmp/example' })
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// The first invocation will take 3s, the rest instantaneous.
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// outputs: 'result'
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getData('some input')
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.then(console.log)
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// check the cache for output generated with this input.
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// cache.read() will resolve on hit, reject on miss.
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function getData (input) {
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return cache
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.read(input)
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.catch(() => expensiveOperation(input))
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}
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// The expensive operation we're aiming to avoid,
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// (3 second cost per invocation)
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function expensiveOperation (input) {
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return new Promise((resolve, reject) => {
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setTimeout(() => {
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const output = 'result'
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cache.write(input, output)
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resolve(output)
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}, 3000)
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})
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}
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```
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* [cache-point](#module_cache-point)
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* [Cache](#exp_module_cache-point--Cache) ⏏
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* [new Cache([options])](#new_module_cache-point--Cache_new)
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* [.dir](#module_cache-point--Cache+dir) : <code>string</code>
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* [.read(keys)](#module_cache-point--Cache+read) ⇒ <code>Promise</code>
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* [.readSync(keys)](#module_cache-point--Cache+readSync) ⇒ <code>string</code>
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* [.write(keys, content)](#module_cache-point--Cache+write) ⇒ <code>Promise</code>
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* [.writeSync(keys, content)](#module_cache-point--Cache+writeSync)
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* [.getChecksum(keys)](#module_cache-point--Cache+getChecksum) ⇒ <code>string</code>
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* [.clear()](#module_cache-point--Cache+clear) ⇒ <code>Promise</code>
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* [.remove()](#module_cache-point--Cache+remove) ⇒ <code>Promise</code>
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<a name="exp_module_cache-point--Cache"></a>
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### Cache ⏏
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**Kind**: Exported class
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<a name="new_module_cache-point--Cache_new"></a>
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#### new Cache([options])
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| Param | Type |
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| --- | --- |
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| [options] | <code>object</code> |
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| [options.dir] | <code>string</code> |
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<a name="module_cache-point--Cache+dir"></a>
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#### cache.dir : <code>string</code>
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Current cache directory. Can be changed at any time.
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**Kind**: instance property of [<code>Cache</code>](#exp_module_cache-point--Cache)
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<a name="module_cache-point--Cache+read"></a>
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#### cache.read(keys) ⇒ <code>Promise</code>
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A cache hit resolves with the stored value, a miss rejects.
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**Kind**: instance method of [<code>Cache</code>](#exp_module_cache-point--Cache)
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| Param | Type | Description |
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| --- | --- | --- |
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| keys | <code>\*</code> | One or more values to uniquely identify the data. Can be any value, or an array of values of any type. |
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<a name="module_cache-point--Cache+readSync"></a>
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#### cache.readSync(keys) ⇒ <code>string</code>
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A cache hit returns the stored value, a miss returns `null`.
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**Kind**: instance method of [<code>Cache</code>](#exp_module_cache-point--Cache)
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| Param | Type | Description |
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| --- | --- | --- |
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| keys | <code>\*</code> | One or more values to uniquely identify the data. Can be any value, or an array of values of any type. |
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<a name="module_cache-point--Cache+write"></a>
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#### cache.write(keys, content) ⇒ <code>Promise</code>
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Write some data to the cache. Returns a promise which resolves when the write is complete.
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**Kind**: instance method of [<code>Cache</code>](#exp_module_cache-point--Cache)
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| Param | Type | Description |
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| --- | --- | --- |
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| keys | <code>\*</code> | One or more values to index the data, e.g. a request object or set of function args. |
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| content | <code>\*</code> | the data to store |
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<a name="module_cache-point--Cache+writeSync"></a>
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#### cache.writeSync(keys, content)
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Write some data to the cache with a key.
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**Kind**: instance method of [<code>Cache</code>](#exp_module_cache-point--Cache)
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| Param | Type | Description |
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| --- | --- | --- |
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| keys | <code>\*</code> | One or more values to index the data, e.g. a request object or set of function args. |
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| content | <code>\*</code> | the data to store |
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<a name="module_cache-point--Cache+getChecksum"></a>
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#### cache.getChecksum(keys) ⇒ <code>string</code>
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Used internally to convert a key value into a hex checksum. Override if for some reason you need a different hashing strategy.
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**Kind**: instance method of [<code>Cache</code>](#exp_module_cache-point--Cache)
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| Param | Type | Description |
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| --- | --- | --- |
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| keys | <code>\*</code> | One or more values to index the data, e.g. a request object or set of function args. |
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<a name="module_cache-point--Cache+clear"></a>
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#### cache.clear() ⇒ <code>Promise</code>
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Clears the cache. Returns a promise which resolves once the cache is clear.
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**Kind**: instance method of [<code>Cache</code>](#exp_module_cache-point--Cache)
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<a name="module_cache-point--Cache+remove"></a>
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#### cache.remove() ⇒ <code>Promise</code>
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Clears and removes the cache directory. Returns a promise which resolves once the remove is complete.
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**Kind**: instance method of [<code>Cache</code>](#exp_module_cache-point--Cache)
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* * *
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© 2016-19 Lloyd Brookes \<75pound@gmail.com\>. Documented by [jsdoc-to-markdown](https://github.com/jsdoc2md/jsdoc-to-markdown).
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