6.0.0 • Public • Published

Koop Memory Cache

npm version coverage

This is a LRU cache with ttl (time to live) expiry. It expects cache items to be GeoJSON feature collections. It is based on quick-lru.

Cache eviction occurs in two ways:

  1. if the cache grows to a number of items greater than the cache's defined size, the least recently inserted or accessed item is evicted
  2. if a item is accessed and it has gone past its ttl period, it is evicted


Stand-alone instantiation:

const Cache = require('@koopjs/cache-memory');
const cache = new Cache({ size: 1000 });

As a Koop cache plugin

This is the default cache for Koop so you won't need to instantiate it yourself. If you really wanted to, it would look like this:

const Koop = require('koop')
const koop = new Koop()
const cache = require('@koopjs/cache-memory')
koop.register(cache, { size: 1000 })


size: the maximum number of items to store in the queue before evicting the least recently used item.

Cache API

The cache is a JavaScript object that lives in-memory. It is used to store geojson features.


Insert geojson into the cache.

const geojson = {
  type: 'FeatureCollection',
  features: [],
  metadata: { 
    name: 'Example GeoJSON',
    description: 'This is geojson that will be stored in the cache'

const options = {
  ttl: 1000 // The TTL option is measured in seconds, it will be used to set the `maxAge` property in the LRU cache

cache.insert('key', geojson, options, err => {
  // This function will call back with an error if one occurs


Retrieve a cached feature collection.

const options = {
  pick: [] // an array of keys used to return a subset of the feature collections root level properties

cache.retrieve('key', options, (err, geojson) => {
  /* This function will callback with an error or the data cached with the passed key. It will return undefined if not found or expired.
    type: 'FeatureCollection',
    features: [],
    metadata: {}


Remove a feature collection from the cache

cache.delete('key', err => {
  // This function will call back with an error if one occurs



Package Sidebar


npm i @koopjs/cache-memory

Weekly Downloads






Unpacked Size

5.24 kB

Total Files


Last publish


  • sanshr
  • drspacemanphd
  • sonofflynn89
  • tomtom92
  • haoliang
  • richgwozdz
  • dhatcher