attic

Attic synchronizes persistent storage such as localStorage with an object in memory to reduce access time. In addition, it can track the lifetime of an element and discard it if it is too old. To minimize null values, you must specify a fallback (for example, an API query) each time you read from the cache. If an element does not exist or the lifetime of an element has expired, the fallback function is used and the result of this function is stored with the ID passed in the Get function. This means that the cache does not have to be filled explicitly via a set function (although the possibility exists in Attic).

Installation

// with npm
npm install @fwieland/attic

// with yarn
yarn add @fwieland/attic

Usage

Here is a quick example to get you started:

import Attic from '@fwieland/attic';

const cache = new Attic("storageName", {
	lifetime: 10000, //10sec
})

cache.get("id1")
	.fallback(() => fetch('https://jsonplaceholder.typicode.com/todos/1').then(r => r.json())
	.then(content => console.log(content));

To reduce the boilerplate of extracting the json (in case of API-Requests) attic allows to specify a fallbackExtractor function.

const cache = new Attic("storageName", {
	fallbackExtractor: (r) => r.json(),
})

cache.get("id1")
	.fallback(() => fetch('https://jsonplaceholder.typicode.com/todos/1'))
	.then(content => console.log(content));

Options

You can provide different options to customize and extend attic: The provided examples are the default values of attic.

const cache = new Attic("storageName", {

	// spezifies the liftime of a item
	liftime: null,

	// will get called on the fallback promise
	fallbackExtractor: (e) => e, 

	// On default attic will load the spezific item into memory if it is the first time requested.
	// If synOnInit is true attic will load all items that are stored in the persitentCache into the memoryCache.
	syncOnInit: false, 

	// memoryCache, TS-Interface: ICache
	memoryCache: new MemoryCache(),	

	//localStorage, TS-Interface: ICache
	persistentCache: new PersistentCache(), 
})