An abstraction of NodeCache that supports a max size option
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An abstraction of the NodeCache memory cache that supports a max size option.

Build status

Node.js Versions

Supports 0.12.x and above.


npm i --save capped-cache


The API essentially matches that of NodeCache, but with a couple of additional behaviours.

function CappedCache([options])

A constructor function that creates a new instance of CappedCache, with an associated NodeCache instance under the hood. options is an optional object that permits the configuration of the cache:

  • maxSize - the maximum number of objects that CappedCache can store at any given time
  • defaultTTL - the default TTL, in seconds, for objects stored in the cache

So that performance isn't compromised, the instance of NodeCache created under the hood will have its useClones option set to false.


Gets the object associated with the specified cache key. cacheKey must be a String. If the key is not found, then this method will return undefined.

CappedCache.prototype.set(cacheKey, data, [ttl])

Stores an object in the cache with the associated key. An optional TTL can be passed if one wishes to override the default.

This method returns a Boolean that reflects whether the item was successfully stored:

  • If the number of stored items exceeds the configured maxSize, then this will return false, and the item will not be stored
  • In all other cases, the item will be stored, and this method will return true.


Flushes all data from the cache.

Local development


  1. Fork this repo
  2. Clone said fork
  3. npm i

Unit tests

Unit tests are written with Mocha, Chai, and Sinon. Run with npm test.


Definitely more than happy to accept pull requests. Just be sure to use tabs instead of spaces, as this is the existing formatting convention.