lru
A simple LRU cache supporting O(1) set, get and eviction of old keys
Installation
$ npm install lru
Example
var LRU = ; var cache = 2 evicted cache; cache;cache; //=> bar cache;cache; //=> bar2 cache; // => evicted = { key: 'foo', value: 'bar' }cache; // => 'bar3'cache // => 'bar2'cache // => undefinedcachelength // => 1cachekeys // => ['foo3'] cacheclear // => it will NOT emit the 'evict' eventcachelength // => 0cachekeys // => []
API
LRU( length )
Create a new LRU cache that stores length
elements before evicting the least recently used.
Optionally you can pass an options map with additional options:
max: maxElementsToStore maxAge: maxAgeInMilliseconds
If you pass maxAge
items will be evicted if they are older than maxAge
when you access them.
Returns: the newly created LRU cache
Properties
.length
The number of keys currently in the cache.
.keys
Array of all the keys currently in the cache.
Methods
.set( key, value )
Set the value of the key and mark the key as most recently used.
Returns: value
.get( key )
Query the value of the key and mark the key as most recently used.
Returns: value of key if found; undefined
otherwise.
.peek( key )
Query the value of the key without marking the key as most recently used.
Returns: value of key if found; undefined
otherwise.
.remove( key )
Remove the value from the cache.
Returns: value of key if found; undefined
otherwise.
.clear()
Clear the cache. This method does NOT emit the evict
event.
.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