cache-point

cache-point

A memoisation solution intended to cache the output of expensive operations, speeding up future invocations with the same input.

Example

const Cache = require('cache-point')
const cache = new Cache({ dir: 'tmp/example' })

// endure a 3s wait for the result
function expensiveOperation (input) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      const output = 'result'
      cache.write(input, output)
      resolve(output)
    }, 3000)
  })
}

// check the cache for output generated with this input.
// cache.read() will resolve on hit, reject on miss.
function getData (input) {
  return cache
    .read(input)
    .catch(() => expensiveOperation(input))
}

// The first invocation will take 3s, the rest instantaneous.
getData('some input')
  .then(console.log)

// outputs: 'result'

• 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.

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.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

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© 2016 Lloyd Brookes <[e-mail]>. Documented by jsdoc-to-markdown.