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diff --git a/node_modules/lru-cache/README.md b/node_modules/lru-cache/README.md new file mode 100644 index 000000000..c06814e04 --- /dev/null +++ b/node_modules/lru-cache/README.md @@ -0,0 +1,137 @@ +# lru cache + +A cache object that deletes the least-recently-used items. + +## Usage: + +```javascript +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. + +## Keys should always be Strings or Numbers + +Note: this module will print warnings to `console.error` if you use a +key that is not a String or Number. Because items are stored in an +object, which coerces keys to a string, it won't go well for you if +you try to use a key that is not a unique string, it'll cause surprise +collisions. For example: + +```JavaScript +// Bad Example! Dont' do this! +var cache = LRU() +var a = {} +var b = {} +cache.set(a, 'this is a') +cache.set(b, 'this is b') +console.log(cache.get(a)) // prints: 'this is b' +``` + +## Options + +* `max` The maximum size of the cache, checked by applying the length + function to all values in the cache. 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 `max` + 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. +* `stale` By default, if you set a `maxAge`, it'll only actually pull + stale items out of the cache when you `get(key)`. (That is, it's + not pre-emptively doing a `setTimeout` or anything.) If you set + `stale:true`, it'll return the stale value before deleting it. If + you don't set this, then it'll return `undefined` when you try to + get a stale entry, as if it had already been deleted. + +## API + +* `set(key, value, maxAge)` +* `get(key) => value` + + Both of these will update the "recently used"-ness of the key. + They do what you think. `max` is optional and overrides the + cache `max` option if provided. + +* `peek(key)` + + Returns the key value (or `undefined` if not found) without + updating the "recently used"-ness of the key. + + (If you find yourself using this a lot, you *might* be using the + wrong sort of data structure, but there are some use cases where + it's handy.) + +* `del(key)` + + Deletes a key out of the cache. + +* `reset()` + + Clear the cache entirely, throwing away all values. + +* `has(key)` + + Check if a key is in the cache, without updating the recent-ness + or deleting it for being stale. + +* `forEach(function(value,key,cache), [thisp])` + + Just like `Array.prototype.forEach`. Iterates over all the keys + in the cache, in order of recent-ness. (Ie, more recently used + items are iterated over first.) + +* `keys()` + + Return an array of the keys in the cache. + +* `values()` + + Return an array of the values in the cache. + +* `length()` + + Return total length of objects in cache taking into account + `length` options function. + +* `itemCount` + + Return total quantity of objects currently in cache. Note, that + `stale` (see options) items are returned as part of this item + count. + +* `dump()` + + Return an array of the cache entries ready for serialization and usage + with 'destinationCache.load(arr)`. + +* `load(cacheEntriesArray)` + + Loads another cache entries array, obtained with `sourceCache.dump()`, + into the cache. The destination cache is reset before loading new entries |