lru-cache-promise

lru-cache with promises

This library wraps Isaac Z. Schlueter's lru-cache and adds a getAsync function.

Usage:

``javascript
var cache = require("lru-cache-promise")();

var fetchFunction = function(key) {
/ Do something async here to fetch the value /
};

cache.getAsync("some key", fetchFunction)
.then(function(value) { console.log(value) });
``

getAsync returns an A+ (specifically bluebird) promise.
* If the value has already been cached, the promise will resolve immediately
* If not, fetchFunction will be called with the requested key. fetchFunction must return either a concrete value or a promise.

getAsync ensures only one call to fetchFunction for a given key,
allowing the calling code to be make many concurrent calls for the same key
without negatively impacting the system from which the values are fetched.