lru-cache

lru cache

A cache object that deletes the least-recently-used items.

Usage:

var LRU = require("lru-cache")
  , options = { max: 500
              , length: function (n) { return n * 2 }
              , dispose: function (key, n) { n.close() }
              , maxAge: 1000 * 60 * 60 }
  , cache = LRU(options)
  , otherCache = LRU(50) // sets just the max size

cache.set("key", "value")
cache.get("key") // "value"

cache.reset()    // empty the cache

If you put more stuff in it, then items will fall out.

If you try to put an oversized thing in it, then it'll fall out right away.

Options

• max The maximum number of items. Not setting this is kind of silly, since that's the whole purpose of this lib, but it defaults to Infinity.
• maxAge Maximum age in ms. Items are not pro-actively pruned out as they age, but if you try to get an item that is too old, it'll drop it and return undefined instead of giving it to you.
• length Function that is used to calculate the length of stored items. If you're storing strings or buffers, then you probably want to do something like function(n){return n.length}. The default is function(n){return 1}, which is fine if you want to store n like-sized things.
• dispose Function that is called on items when they are dropped from the cache. This can be handy if you want to close file descriptors or do other cleanup tasks when items are no longer accessible. Called with key, value. It's called before actually removing the item from the internal cache, so if you want to immediately put it back in, you'll have to do that in a nextTick or setTimeout callback or it won't do anything.

Similar packages

Other packages similar to lru-cache

node-cache

node-cache is an in-memory cache module for Node.js. It is similar to lru-cache but does not specifically implement the LRU (Least Recently Used) cache algorithm. Instead, it provides a simple caching mechanism with TTL (time to live) support.

cache-manager

cache-manager is a cache module that allows easy switching between different cache stores. It supports a variety of stores (e.g., memory, Redis, MongoDB) and includes LRU cache functionality. It is more flexible than lru-cache in terms of storage options but may be more complex to use.

quick-lru

quick-lru is an LRU cache implementation that is optimized for performance. It claims to be faster than lru-cache for certain use cases, especially when dealing with a large number of items or frequent evictions.