localStorage class

CacheCollection.js

// src/utils/CacheCollection.js
/**
 * Creates a collection of unique values in local storage
 * Works with arrays only
 * Singleton method to allow sharing between classes without adding extra stuff
 */
class CacheCollection {
    constructor (key, expire=1200) {
        this.key = key;
        this.expire = expire;
        this.items = this.getall();
    }
    add(el) {
        if (!this.has(el) && el!== '') {
            this.items.push(el.toString() || el);
            console.log('[CacheCollection] add: ', el, this.items);
        }
        this.store();
    }
    del(el) {
        let idx = this.indexOf(el)
        if (idx !== -1) {
            this.items.splice(idx,1);
        }
        this.store();
    }
    has(el) {
        return this.indexOf(el) !== -1;
    }
    indexOf(el) {
        el = el.toString() || el;
        return this.items.indexOf(el);
    }
    store() {
        localStorage.setItem(this.key, JSON.stringify(this.items));
        localStorage.setItem(this.key+':ts', Date.now());
    }

    getall() {
        let  stored = localStorage.getItem(this.key);
        console.log(stored);
        return (this.isExpired() || !stored) ?
        [] :
        JSON.parse(stored);
    }

    isExpired(){
        let whenCached = localStorage.getItem(this.key + ':ts')
        let age = (Date.now() - whenCached) / 1000
        console.log('[CachedColletion] is Expired', age>this.expire );
        if (age > this.expire) {
            this.clear();
            return true;
        } else {
            return false;
        }
    }
    clear() {
        localStorage.removeItem(this.key)
        localStorage.removeItem(this.key + ':ts')
    }
}
/**
 * Caches objects as singletons. Alternative, can ignore this.items and just load
 * always from localStorage.
 * @type {Object}
 */

let cache = {};
/**
 * [getSingleton description]
 * @method getSingleton
 * @param  {string}     key           Key for localStorage
 * @param  {Number}     [expire=1200] Expiration time in seconds
 * @param  {String}     [sep=',']     separator in case. Default: ,
 * @return {CacheCollection}          A singleton of CacheCollection
 */
function getSingleton(key, expire=1200) {
    if (!cache.hasOwnProperty(key)) {
        // console.log('[getSingleton] Not in cache');
        cache[key] = new CacheCollection(key, expire);
    }
    // console.log('[getSingleton]', cache[key]);
    return cache[key];
}
export {getSingleton, CacheCollection};