memory-cacheable
v1.2.2
Published
minimal in memory completely volatile cache store with a "stale concept"
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cacheable
I built this because I had the need to store expensive and frequently called functions into memory. It's not a framework for caches, it's not really a class, or a cache wrapper. It's minimal, and encourages you to decide how you want to interact with the available states of your cached collections. Think of this as a function that keeps state of points in time, with a couple helpers to manage cached collections.
install
npm install --save memory-cacheable
api
cacheable({ key, cache, ttl, offset, verbose })
see below table for options:
| key | required | summary |
| --- | --- | --- |
| key
| false
| key for debugging purposes, mostly |
| ttl
| false
| defaults to 1 hour, uses the ms
module for easy formatting |
| cache
| false
| defaults to an array, but will also support cleaning out objects |
| offset
| false
| defaults to 0.65
(roughly 2/3 the ttl
), used to create the stale value by multiplying the ttl
by offset
|
| verbose
| false
| defaults to false
turn this on for really noisey cache stats and debugging |
cacheable api
| function
| summary |
| --- | --- |
| cacheable(store).debug()
| debug logging, noisey, expensive stuff |
| cacheable(store).expired()
| check if cache state is expired |
| cacheable(store).fetch()
| fetches the cached collection |
| cacheable(store).flush()
| flush cache, supports Objects
and Arrays
|
| cacheable(store).set(collection)
| sets cached collection from provided param |
| cacheable(store).size()
| gets the cache size, if an object Object.keys()
is called |
| cacheable(store).stale()
| determines if the cache is stale or not |
| cacheable(store).state()
| returns whether the cache is expired or not, if cache is expired, state
will reset
and flush
the cache |
| cacheable(store).reset()
| restarts timers, will not flush cache |
example
const { cacheable } = require('memory-cacheable');
const store = {
key: 'expensiveCacheExample',
ttl: '1h'
};
const expired = cacheable(store).state; // pulls state out to manage state and check if expired
const { stale, reset, flush } = cacheable(store); // other helpful tings
// simplest example usage
function doSomethingExpensive(fn) {
if (!expired()) return fn(null, store.cache);
return funcToExpensiveThings((err, resp) => {
if (err) return fn(new Error(err), null);
store.cache = resp;
return fn(null, resp);
});
}
// example usage for expensive or long running functions with
// stale support
function doSomethingExpensive(fn) {
const isStale = stale();
if (!expired() && !isStale) return fn(null, store.cache);
if (isStale) fn(null, store.cache);
return funcToExpensiveThings((err, resp) => {
if (err) return fn(new Error(err), null);
store.cache = resp;
if (isStale) return reset();
return fn(null, resp);
});
}
debugging
Uses the debug
module, and you can set the following environment variable:
export DEBUG=cacheable:*
test
npm install --save-dev && npm test