Storage Utilities

Browser-specific storage utilities.

Classes

LocalStorageCache

LocalStorage-based cache implementation that implements the CacheStore interface from @outilx/core.

class LocalStorageCache implements CacheStore {
  constructor(prefix?: string)
  get(key: string): Promise<any>
  set(key: string, value: any): Promise<void>
  clear(): void
  delete(key: string): void
  has(key: string): boolean
}

Constructor

• prefix - Key prefix for localStorage items (default: 'async_cache_')

Methods

get(key)

Retrieves a value from localStorage.

const cache = new LocalStorageCache('my_app_');
const data = await cache.get('user'); // Returns parsed JSON or undefined

set(key, value)

Stores a value in localStorage as JSON.

await cache.set('user', { name: 'John', age: 30 });

clear()

Removes all items with the cache prefix from localStorage.

cache.clear(); // Removes all 'my_app_*' keys

delete(key)

Removes a specific item from localStorage.

cache.delete('user');

has(key)

Checks if a key exists in localStorage.

if (cache.has('user')) {
  // Key exists
}

Examples

Basic Usage

import { LocalStorageCache } from '@outilx/browser';

const cache = new LocalStorageCache('app_');

// Store data
await cache.set('settings', { theme: 'dark', lang: 'en' });

// Retrieve data
const settings = await cache.get('settings');
console.log(settings); // { theme: 'dark', lang: 'en' }

// Check existence
cache.has('settings'); // true

// Delete
cache.delete('settings');
cache.has('settings'); // false

With createAsyncProcessor

import { createAsyncProcessor, LocalStorageCache } from '@outilx/browser';

function fetchUser(id: number, cb: (err: any, result: any) => void) {
  fetch(`/api/users/${id}`)
    .then(res => res.json())
    .then(data => cb(null, data))
    .catch(err => cb(err, null));
}

// Create processor with persistent cache
const getUser = createAsyncProcessor(fetchUser, {
  cache: new LocalStorageCache('user_cache_'),
  keyGenerator: (id) => `user_${id}`
});

// First call - fetches from API
const user = await getUser(123);

// Subsequent calls (even after page reload) - returns from localStorage
const cachedUser = await getUser(123);

WARNING

LocalStorageCache stores data as JSON strings. Make sure your data is JSON-serializable.

TIP

Use MemoryCache from @outilx/core for non-persistent caching that works in any environment.