Gorgon

A typescript async based caching library for node or the browser.

Pass in a cache key, an async function and optionally a cache length and get back a cached object.

Installation

npm install @gorgonjs/gorgon

yarn add @gorgonjs/gorgon

pnpm add @gorgonjs/gorgon

Usage

See http://gorgonjs.dev for full documentation

API

get = function(key, asyncFunction, policy)

The function will lookup and resolve the value for the previously resolved promise, if no entry is in the cache the function will resolve the promise and resolve that.

Functions that throw errors are not cached. or if they return undefined.

The policy value will set the duration of the cache, if no policy is set the object will be cache until cleared manually.

overwrite = function(key, asyncFunction, policy)

The function will resolve the value for the asnc function and store that result in place of the current object. The original object will be available while the function resolves.

Functions that throw errors are not cached. or if they return undefined.

The policy value will set the duration of the cache, if no policy is set the object will be cache until cleared manually.

put = function(key, value, policy)

Bypass the get function and store an object directly into the cache.

clear = function(key, provider)

Clear a cached item, if no key is set all items will be cleared. Returns a promise that will resolve to true if successful, or an array of booleans for each key; if provider is not specified it will clear the default provider only.

You may also clear cache items using a wildcard characters e.g. Gorgon.clear('sample*')

settings = function(newSettings)

Send in an updated settings object:

• debug: will output logging
• retry: will allow for the concurrency queue to be bypassed after this interval, default: 5000

Policies

Simple Policy

The simplest policy is to simply set a duration, pass in any integer and the object will be cached for that many miliseconds.

Gorgon.get('sample', resolver, 1000).then(res => { console.log(res); });

Date Policy

If you have a specific date and time you would like a cache item to expire, you can pass in a date object

var midnight = new Date();
midnight.setHours(24,0,0,0); // midnight
Gorgon.get('sample', resolver, midnight).then(res => { console.log(res); });

Complex Policy

If you have something more complex you would like to do with the policy, you can pass in an object with your specifications.

Properties

• expiry: Date or amount of milliseconds you would like the cache to expire (required but may be set to false)
• provider: Specify the provider to use (default: 'memory')

Example

Gorgon.get('sample', resolver, {
  expiry: 1000,
  provider: 'memory',
}).then(res => { console.log(res); });

Alternate Storage Engines

var Gorgon = require('@gorgonjs/gorgon');
var storageCache = require('@gorgonjs/gorgon/storageObjectProvider');
storageCache.setStorage(window.sessionStorage);

Gorgon.addProvider('session', storageCache);

More

Concurrency

If you request 2 calls at the same time with the same key, the resolver will only resolve once no matter how long the resolver takes. Making a slow API call will only call the API once even if you request the information more then once in a short period. This can be used to help reduce trips to external systems.