lru

A simple LRU cache supporting O(1) set, get and eviction of old keys

Installation

$ npm install lru

Example

var LRU = require('lru').LRU;

var cache = new LRU(2),
    evicted

cache.on('evict',function(data) { evicted = data });

cache.set('foo', 'bar');
cache.get('foo'); //=> bar

cache.set('foo2', 'bar2');
cache.get('foo2'); //=> bar2

cache.set('foo3', 'bar3');
cache.get('foo3'); //=> bar3,  evicted = { key: 'foo', value: 'bar' }

API

require('lru').LRU( length )

Create a new LRU cache that stores length elements before evicting the least recently used.

Returns: the newly created LRU cache

Methods

.set( key, value )

Set the value of the key and mark the key as most recently used.

Returns: value

.set( key, value )

Set the value of the key and mark the key as most recently used.

.get( key )

Query the value of the key and mark the key as most recently used.

Returns: value of key if found; undefined otherwise.

.on( event, callback )

Respond to events. Currently only the evict event is implemented. When a key is evicted, the callback is executed with an associative array containing the evicted key: {key: key, value: value}.

Credits

A big thanks to Dusty Leary who finished the library.

License

MIT