TheStorage ·

A storage that automatically removes the least-recently-used items.

Features

• Fast LRU implementation
• Gzipped version has less than 400 bytes
• Minimalist API
• Supports to both Node and Browser
• Supports to Types
• Zero-dependency

Installation

To install the-storage, execute:

$ npm install the-storage

or

$ yarn add the-storage

Quickstart

TheStorage is a cache class which is designed to keep storing just the most recently used items. To ensure it, the class receives a capacity, that will be used to discard the least recently used items when the capacity is reached.

import TheStorage from 'the-storage';

// `capacity` is required and it must to be a posite integer
const storage = new TheStorage(3);

storage.setItem('key1', 'value1');
storage.setItem('key2', 'value2');
storage.getItem('key1'); // 'value1'
storage.setItem('key3', 'value3');

// At this point, the item associeted with `key2` will be evicted.
// It happens because the capacity was reached and `key1` was used before `key2`.
storage.setItem('key4', 'value4');

storage.size(); // 3
storage.contains('key2'); // false
storage.contains('key1'); // true

Methods

contains(key: any): boolean Checks if the given key exist within the storage

setItem(key: any, value: any): boolean Adds the key-value pair to the cache if the key is not in the cache yet. Otherwise, if the key exists, updates the value of the key. In case the current number of keys exceeds the capacity, then it evicts the least recently used key that is not marked as persistent.

getItem(key: any): any Retrieves the value associeted with the given key if it exists in the cache. If the key is not in the cache, it returns undefined.

removeItem(key: any): boolean Deletes item and returns true if the item existed in the storage - persistent will be removed as well. Returns false if the element doesn't exist in the storage.

setPersistent(key: any): void Makes item persistent, i.e the item can no longer be automatically evicted. However, the item still will be removed when invoking removeItem or clear.

import TheStorage from 'the-storage';

const storage = new TheStorage(3);
storage.setItem('key1', 'value1');
storage.setPersistent('key1');
storage.setItem('key2', 'value2');
storage.setItem('key3', 'value3');

// At this point the item associeted with `key2` will be evicted
// since the `key1` is marked as `persistent` and can not be evicted.
storage.setItem('key4', 'value4');

storage.contains('key1'); // true
storage.contains('key2'); // false

removePersistent(key: any): void Makes item no longer a persistent item.

togglePersistent(key: any): void Makes item persistent if it was not yet, or otherwise undo the persistent flag.

size(): number Returns the storage size.

clear(): void Remove all items - even the persistent ones - from the cache.

LICENSE

MIT