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isaacs
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README.md
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 toInfinity
.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 likefunction(n){return n.length}
. The default isfunction(n){return 1}
, which is fine if you want to storen
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 withkey, 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 anextTick
orsetTimeout
callback or it won't do anything.