flat-cache

What is flat-cache?

The flat-cache package is a simple disk-based key-value store that allows you to set and get data, cache it on disk, and clear the cache when necessary. It is useful for caching results of expensive operations, storing configuration, or any other use case where a simple persistent key-value store is needed.

What are flat-cache's main functionalities?

Caching data to disk

This feature allows you to cache data to disk by setting a key-value pair and then saving the cache. The data can be retrieved later, even after the process is restarted.

const flatCache = require('flat-cache');
let cache = flatCache.load('myCache');
cache.setKey('key', 'value');
cache.save();

Loading cached data from disk

This feature allows you to load previously saved cache from disk and retrieve the value associated with a specific key.

const flatCache = require('flat-cache');
let cache = flatCache.load('myCache');
let value = cache.getKey('key');

Removing a specific key from the cache

This feature allows you to remove a specific key from the cache and then save the updated cache to disk.

const flatCache = require('flat-cache');
let cache = flatCache.load('myCache');
cache.removeKey('key');
cache.save();

Clearing the entire cache

This feature allows you to clear the entire cache and then save the empty cache to disk, effectively resetting it.

const flatCache = require('flat-cache');
let cache = flatCache.load('myCache');
cache.clearAll();
cache.save();

Other packages similar to flat-cache

node-cache

node-cache is an in-memory caching module. It is similar to flat-cache in providing simple key-value storage, but it does not persist the cache to disk by default.

memory-cache

memory-cache is another in-memory key-value store that is similar to flat-cache. It is designed for caching objects in memory and does not include built-in disk persistence.

localforage

localforage is a fast and simple storage library for JavaScript. It improves upon flat-cache by providing a more powerful API and support for IndexedDB, WebSQL, and localStorage, which can be used for client-side storage in web applications.

keyv

keyv is a simple key-value storage with support for multiple backends, including MongoDB, SQLite, PostgreSQL, and more. Unlike flat-cache, keyv is more versatile due to its support for various storage adapters.

README

flat-cache

A stupidly simple key/value storage using files to persist the data

install

npm i --save flat-cache

Usage

const flatCache = require('flat-cache');
// loads the cache, if one does not exists for the given
// Id a new one will be prepared to be created
const cache = flatCache.load('cacheId');

// sets a key on the cache
cache.setKey('key', { foo: 'var' });

// get a key from the cache
cache.getKey('key'); // { foo: 'var' }

// fetch the entire persisted object
cache.all(); // { 'key': { foo: 'var' } }

// remove a key
cache.removeKey('key'); // removes a key from the cache

// save it to disk
cache.save(); // very important, if you don't save no changes will be persisted.
// cache.save( true /* noPrune */) // can be used to prevent the removal of non visited keys

// loads the cache from a given directory, if one does
// not exists for the given Id a new one will be prepared to be created
const cache = flatCache.load('cacheId', path.resolve('./path/to/folder'));

// The following methods are useful to clear the cache
// delete a given cache
flatCache.clearCacheById('cacheId'); // removes the cacheId document if one exists.

// delete all cache
flatCache.clearAll(); // remove the cache directory

Motivation for this module

I needed a super simple and dumb in-memory cache with optional disk persistance in order to make a script that will beutify files with esformatter only execute on the files that were changed since the last run. To make that possible we need to store the fileSize and modificationTime of the files. So a simple key/value storage was needed and Bam! this module was born.

Important notes

• If no directory is especified when the load method is called, a folder named .cache will be created inside the module directory when cache.save is called. If you're committing your node_modules to any vcs, you might want to ignore the default .cache folder, or specify a custom directory.
• The values set on the keys of the cache should be stringify-able ones, meaning no circular references
• All the changes to the cache state are done to memory
• I could have used a timer or Object.observe to deliver the changes to disk, but I wanted to keep this module intentionally dumb and simple
• Non visited keys are removed when cache.save() is called. If this is not desired, you can pass true to the save call like: cache.save( true /* noPrune */ ).

License

MIT © Jared Wray