/***
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* A simpler cache, using localStorage
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* Mainly used to store settings locally
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* example:
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* -> dark/light mode switch
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* -> view mode selection
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* -> tab navigation direction (for table views)
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**/
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class SimpleCache {
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/**
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*
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* @param {string} base
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* @param {object} config
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* @param {string} config.namespace
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* @param {number} config.TTL
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* @param {number} config.maxSize
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*/
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constructor(base, config = {}) {
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this.base = base;
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this.config = {
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namespace: `${jvbBase.base}cache`,
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TTL: 3600000,
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maxSize: 100,
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...config
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};
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// Initialize memory cache
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this._cache = new Map();
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this.subscribers = new Set();
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}
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/**
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* Clear all memory cache
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* @returns {number} Number of items cleared
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*/
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clearMemoryCache() {
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const count = this._cache.size;
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this._cache.clear();
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console.log(`Cleared ${count} items from memory cache`);
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return count;
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}
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/**
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* Get a setting value
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*/
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get(key) {
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//Check memory cache first
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if (this._cache.has(key)) {
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return this._cache.get(key);
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}
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let cacheKey = `${this.base}_${key}`;
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let item;
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try {
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item = localStorage.getItem(cacheKey);
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if (!item) {
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return null;
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}
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item = JSON.parse(item);
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} catch (error) {
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console.warn('Error getting from localStorage:', error);
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return null;
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}
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if (item) {
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this._cache.set(key, item);
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}
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return item;
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}
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/**
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* Set a setting value
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*/
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set(key, value) {
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this._cache.set(key, value);
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let cacheKey = `${this.base}_${key}`;
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try {
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localStorage.setItem(cacheKey, JSON.stringify(value));
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} catch (error) {
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// Handle quota exceeded
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if (error instanceof DOMException && error.code === 22) {
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this.clearOldestLocalStorageItems();
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try {
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localStorage.setItem(key, JSON.stringify(item));
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} catch (retryError) {
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console.warn('Still failed to set localStorage item after cleanup:', retryError);
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}
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} else {
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console.warn('Error setting localStorage item:', error);
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}
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}
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// Notify subscribers
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this.notify('cache-saved', { key, value });
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}
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remove(key) {
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let cacheKey = `${this.base}_${key}`;
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try {
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localStorage.removeItem(cacheKey);
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} catch (error) {
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console.warn('Error removing localStorage item:', error);
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}
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}
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/**
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* Clear oldest items from localStorage when quota is exceeded
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*/
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clearOldestLocalStorageItems() {
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try {
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const keysToRemove = [];
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// Find all our cache keys
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for (let i = 0; i < localStorage.length; i++) {
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const key = localStorage.key(i);
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if (key.startsWith(this.config.namespace)) {
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try {
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const item = JSON.parse(localStorage.getItem(key));
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keysToRemove.push({ key, timestamp: item.timestamp || 0 });
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} catch (e) {
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// If it's not valid JSON or doesn't have a timestamp, prioritize for removal
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keysToRemove.push({ key, timestamp: 0 });
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}
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}
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}
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// Sort by timestamp (oldest first)
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keysToRemove.sort((a, b) => a.timestamp - b.timestamp);
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// Remove the oldest 20% of items
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const removeCount = Math.max(1, Math.ceil(keysToRemove.length * 0.2));
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for (let i = 0; i < removeCount; i++) {
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if (keysToRemove[i]) {
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localStorage.removeItem(keysToRemove[i].key);
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}
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}
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} catch (error) {
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console.warn('Error cleaning up localStorage:', error);
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}
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}
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async loadFromCache() {
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for (let i = 0; i < localStorage.length; i++) {
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const key = localStorage.key(i);
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// Check if key starts with this cache's base prefix
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if (key.startsWith(`${this.base}_`)) {
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let cleanKey = key.replace(`${this.base}_`, '');
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try {
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// Parse the JSON value before caching
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const value = JSON.parse(localStorage.getItem(key));
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this._cache.set(cleanKey, value);
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} catch (error) {
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console.warn(`Failed to parse cached value for ${key}:`, error);
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}
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}
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}
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}
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/**
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* Clear all cache
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*
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* @returns {Promise<void>}
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*/
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async clear() {
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this._cache.clear();
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try {
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for (let i = localStorage.length - 1; i >= 0; i--) {
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const key = localStorage.key(i);
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if (key && key.startsWith(this.config.namespace)) {
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localStorage.removeItem(key);
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}
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}
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} catch (error) {
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console.warn('Error clearing localStorage cache:', error);
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}
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}
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/**
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* Subscribe to setting changes
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*/
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subscribe(callback) {
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this.subscribers.add(callback);
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return () => this.subscribers.delete(callback);
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}
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/**
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* Notify subscribers
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*/
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notify(event, data) {
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this.subscribers.forEach(cb => cb(event, data));
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}
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}
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window.jvbCache = SimpleCache;
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