npm/node_modules/lru-cache/README.md

lru cache

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

Usage:

var LRU = require("lru-cache")
  , cache = LRU(10) // max 10 items. default = Infinity
cache.set("key", "value")
cache.get("key") // "value"

RTFS for more info.