absir/lru-cache-ts

A typescript implementation of lru cache

LRU Cache TS

This library is inspired from node-lru-cache and is completely written in Typescript with test coverage.

Installation:

npm:

npm install lru-cache-ts

OR

yarn:

yarn add lru-cache-ts

Usage:

import { LRUCache } from 'lru-cache-ts'

type CacheType = any // set this to a fixed type for type-checking
const cache = LRUCache<CacheType>({ max: 100 })

// key needs to be string, value to be same as cache type defined while creating the object
cache.set('key', 'value')
expect(cache.get('key')).toBe('value')

Options:

• max: The maximum size of the cache. Setting it to a non-whole number will throw a TypeError. (Default: Infinity)

API:

• set(key: string, value: CacheType)

• get(key: string) => CacheType

  Both of these will update the "recently used"-ness of the key. If the key is not found, get() will return undefined. key has to be of type string.

• peek(key: string) => CacheType

  Returns the key value (or undefined if not found) without updating the "recently used"-ness of the key.

• del(key: string)

  Deletes a key out of the cache.

• reset()

  Clear the cache entirely, throwing away all values.

• has(key: string) => boolean

  Check if a key is in the cache, without updating the recent-ness

• forEach(function (value: CacheType, key: string))

  Iterates over all the keys in the cache, in order of recent-ness. (i.e., more recently used items are iterated over first.)

• rforEach(function (value: CacheType, key: string))

  The same as cache.forEach(...) but items are iterated over in reverse order. (i.e., less recently used items are iterated over first.)

• length

  Return total length of objects in cache.

• dump() => Array<LRUDumpObject>

  Return an array of the cache entries ready for serialization and usage with destinationCache.load(arr).

• load(cacheEntriesArray: Array<LRUDumpObject>)

  Loads another cache entries array, obtained with sourceCache.dump(), into the cache. The destination cache is reset before loading new entries