exp-asynccache

asynccache

A async cache with a lookup function per key for node js with a different interface than async-cache.

Callback usage:

var cache = new AsyncCache();

cache.lookup("foo", function (resolve) {
  // Find foo asynchronously (or synchronously) then call resolve with the value
  resolve(null, "baz");
}, function (err, value) {
  console.log(value); // value will be "baz"
});

Promise usage:

var cache = new AsyncCache();

var hit = cache.lookup("foo", function (resolve) {
  resolve(null, "baz");
});

hit.then(function (value) {
  console.log(value); // value will be "baz"
});

By default a lru-cache-plus cache with default settings is used to store cached objects but you can provide your own.

var LRU = require("lru-cache-plus"); // any lru-cache compatible cache will do

var cache = new AsyncCache(new LRU({
  max: 500,
  maxAge: 1000 * 60 * 60
});

The resolve function can take more arguments than error and key. It will pass these to the underlying cache's set method. So when using lru-cache-plus you can provide a max age per key:

var cache = new AsyncCache();

cache.lookup("foo", function (resolve) {
  resolve(null, "baz", 1000); // Let foo live for one second
});