js-last-recently-used-cache

simple LRU cache implementation in javascript. It uses a doubly linked list (instance.list) and a hash map (instance.map) to get/add/remove cache elements with O(1) time complexity.

Install

$ npm install --save js-last-recently-used-cache

Usage

import LRY from 'js-last-recently-used-cache'

const cache = new LRU({limitSize: 3});
cache.set('1', 'one')
cache.set('2', 'two')
cache.set('3', 'three')
cache.get('3') // 'three'
cache.get('1') // 'one'
cache.set('4', 'four');
cache.get('4') //four
cache.has('1') // false (bumped out since cache has a size limit of 3)

API

Table of Contents

• LRU
  • has
  • set
  • get
  • size
  • delete
  • mostRecentKey
  • leastRecentKey
  • mostRecentValue
  • leastRecentValue
  • mostRecent
  • leastRecent
  • pop
  • bump
  • bumpNode
  • setSinglePair
  • getNode
  • getNodeValue
  • getNodeKey

LRU

Parameters

• params.limitSize Number size limit (in number of cached elements) (optional, default {})
  • params.limitSize.limitSize (optional, default 100)

has

check if cache contains specific key

Parameters

• key any to check if in cache

Returns Boolean whether or not key is in cache

set

set new data into the cache

Parameters

• args ...any
• key/value (Array<any, any> | Array<Array<any, any>>) pair(s) to store in cache

Returns (Array<Node> | Node) node(s) inserted in doubly linked list

get

Get the data stored in cache by its key

Parameters

• key any identifier of the data to get from cache

Returns any data stored in cache for specified key

size

gets the number of items in the cache

Returns Number

delete

delete a specific value from the cache by its key (delets it from the hashmap and the doubly linked list)

Parameters

• key any to delete from cache

mostRecentKey

Gets the identifier (key) of the last recently used key/value pair stored in cache

Returns any

leastRecentKey

Gets the identifier (key) of the least recently used key/value pair stored in cache

Returns any

mostRecentValue

Gets most recently used value stored in cache

Returns any

leastRecentValue

Gets most recently used value stored in cache

Returns any

mostRecent

Gets most recently used key/value pair stored in cache

Returns Array<any, any> array with key of cached data at index 0 and value at index 1

leastRecent

Gets least recently used key/value pair stored in cache

Returns Array<any, any> array with key of cached data at index 0 and value at index 1

pop

pop the least recently used key/value in the cache (pops the last element of the double linked list and removes it from hashmap)

bump

bump a specific cached data to last recently used (adds it to front of the double linked list list)

Parameters

• key any key of the data to bump

Returns Node new node created at the front of the list with the same cached data

bumpNode

bump a specific node to last recently used (front of the linked list)

Parameters

• node Node node to bump to front of list

Returns Node new node placed at front of list with data of passed node (passed nodeis removed)

setSinglePair

set a single key/value pair in the cache

Parameters

• key any to identify the data with
• value any value to store in cache

Returns Node node created in doubly linked list with data property being an array of [key,value]

getNode

gets the double linked list's node corresponding to specific key

Parameters

• key any cached element key

Returns Node

getNodeValue

gets the value of a specific node from the doubly linked list (gets the second index of the node's data)

Parameters

• node Node node in doubly linked list this.list

Returns any cached value

getNodeKey

gets the key of a specific node from the doubly linked list (gets the second index of the node's data)

Parameters

• node Node node in doubly linked list this.list

Returns any cached key

License

MIT © Guillaume