Uni-Cache

Uni-Cache is a caching library for Node.js applications. It presents a single API across in-memory, file, SQLite, Redis, MongoDB, and ValKey backends, making it straightforward to switch storage engines without rewriting business logic.

Table of Contents

• Features
• Installation
• Quick Start
• Usage
• API
• Backend Guides
• Troubleshooting
• License
• Contributing

Features

• Multiple backends: memory, filesystem, SQLite, Redis, MongoDB, and ValKey.
• Consistent CRUD helpers for both nested keys and entire objects.
• Configurable persistence: sync eagerly on every write, on demand, or on a fixed interval.
• Optional logging hook for integrating with your existing observability tools.

Installation

npm install @iotux/uni-cache

Optional dependencies

• SQLite backend: npm install sqlite sqlite3
• Redis backend: provide a compatible Redis/ValKey client configuration.
• MongoDB backend: supply a MongoDB URI and collection details.

Quick Start

const UniCache = require('@iotux/uni-cache');

async function demo() {
  const cache = new UniCache('demo-cache', { cacheType: 'memory' });
  await cache.init({ counter: 0 }); // Seeds the cache on first run.

  await cache.add('counter', 5);
  await cache.set('user.name', 'Ada Lovelace');

  console.log(await cache.get('counter')); // 5
  console.log(await cache.get('user.name')); // "Ada Lovelace"
}

demo().catch(console.error);

Usage

Choosing a backend

• memory: Fastest option when persistence is not required.
• file: Stores aggregate data in a single JSON file; per-object data is written to separate files.
• sqlite: Lightweight relational persistence suited to single-host deployments.
• redis / valkey: External in-memory datastores for shared caches.
• mongodb: Durable document storage with horizontal scalability.

Aggregate keys vs. object storage

• Use set, get, and delete for scalar values or nested properties (await cache.set('user.profile.email', '[email protected]')).
• Use createObject, retrieveObject, and deleteObject to persist full JSON documents by top-level key (for example one file or SQLite row per customer record).
• The module tracks object-backed keys separately so that nested updates (await cache.set('customer-42.balance', 100)) operate directly on objects stored via createObject.

Sync strategies

• syncOnWrite: true writes through to the backend on every mutation.
• syncOnWrite: false batches writes until await cache.sync() is called.
• syncInterval (seconds) enables periodic flushes.

API

Lifecycle

• new UniCache(name, options) – create an instance.
• init(initialData) – prepare the backend and optionally seed data.
• sync(force) – persist dirty aggregate data and pending object work.
• close() – flush remaining work (if syncOnClose is set) and tear down backend connections.

Aggregate operations

• get(path) – retrieve a value (supports dot notation).
• set(path, value, syncNow) – store a value.
• delete(path, syncNow) – remove a value.
• add(path, count, syncNow) / subtract(path, count, syncNow) – numeric adjustments.
• push(path, element, syncNow) – append to an array.

Whole-object helpers

• createObject(key, payload, syncNow) – persist a top-level object.
• retrieveObject(key) – fetch an object created with createObject.
• deleteObject(key, syncNow) – remove a stored object.

Introspection

• has(path) – determine if a value exists.
• keys() – list top-level keys (aggregate and object-backed).
• count() – count top-level keys.
• clear(syncNow) – remove all data.
• existsObject() / getInMemorySize() – simple state queries.

Backend Guides

In-memory

const cache = new UniCache('session-cache', { cacheType: 'memory', debug: true });
await cache.init();
await cache.set('activeUsers', 10);

File

const cache = new UniCache('settings', {
  cacheType: 'file',
  savePath: './data/settings',
  syncOnWrite: false,
});

await cache.init();
await cache.set('ui.theme', 'dark');
await cache.sync(); // Flush batched changes to disk.

SQLite

const cache = new UniCache('telemetry', {
  cacheType: 'sqlite',
  savePath: './data/sqlite',
  syncOnWrite: false,
});

await cache.init();
await cache.createObject('meter-001', { watts: 1200, lastUpdated: Date.now() }, false);
await cache.set('meter-001.lastUpdated', Date.now(), false);
await cache.sync(); // Uses incremental upserts to avoid rewriting the whole table.

Redis / ValKey

const cache = new UniCache('sessions', {
  cacheType: 'redis',
  redisConfig: { host: '127.0.0.1', port: 6379 },
  syncOnWrite: true,
});

await cache.init();
await cache.set('user:42.token', 'abc123');
await cache.close();

MongoDB

const cache = new UniCache('feature-flags', {
  cacheType: 'mongodb',
  mongoUri: 'mongodb://localhost:27017',
  dbName: 'configs',
  collectionName: 'flags',
  syncOnWrite: true,
});

await cache.init();
await cache.set('flags.betaUsers', ['ada', 'grace']);

Troubleshooting

• SQLite: Uni-Cache enables WAL mode for better concurrency. Ensure the user running your app can create the database file and parent directories. Install both sqlite and sqlite3 packages before initialising the backend.
• File backend: Keep object keys free of path separators; each object is written to <savePath>/<key>.json.
• Redis/ValKey: Provide a reachable host/port combination and close the cache to release the connection cleanly.

License

Distributed under the MIT License. See LICENSE for details.

Contributing

Issues and pull requests are welcome. Please describe the backend(s) involved and any reproduction steps when reporting bugs.