Cache-manager NPM

cache-manager

Simple and fast NodeJS caching module.

A cache module for NodeJS that allows easy wrapping of functions in cache, tiered caches, and a consistent interface.

Made with Typescript and compatible with ESModules.
Easy way to wrap any function in cache, supports a mechanism to refresh expiring cache keys in background.
Tiered caches -- data gets stored in each cache and fetched from the highest priority cache(s) first.
nonBlocking option that optimizes how the system handles multiple stores.
Use with any Keyv compatible storage adapter.
100% test coverage via vitest.

We moved to using Keyv which are more actively maintained and have a larger community.

A special thanks to Tim Phan who took cache-manager v5 and ported it to Keyv which is the foundation of v6. 🎉 Another special thanks to Doug Ayers who wrote promise-coalesce which was used in v5 and now embedded in v6.

If you are looking for older documentation you can find it here:

Installation

npm install cache-manager

By default, everything is stored in memory; you can optionally also install a storage adapter; choose one from any of the storage adapters supported by Keyv:

npm install @keyv/redis
npm install @keyv/memcache
npm install @keyv/mongo
npm install @keyv/sqlite
npm install @keyv/postgres
npm install @keyv/mysql
npm install @keyv/etcd

In addition Keyv supports other storage adapters such as lru-cache and CacheableMemory from Cacheable (more examples below). Please read Keyv document for more information.

Quick start

import { Keyv } from 'keyv';
import { createCache } from 'cache-manager';

// Memory store by default
const cache = createCache()

// Single store which is in memory
const cache = createCache({
  stores: [new Keyv()],
})

Here is an example of doing layer 1 and layer 2 caching with the in-memory being CacheableMemory from Cacheable and the second layer being @keyv/redis:

import { Keyv } from 'keyv';
import KeyvRedis from '@keyv/redis';
import { CacheableMemory } from 'cacheable';
import { createCache } from 'cache-manager';

// Multiple stores
const cache = createCache({
  stores: [
    //  High performance in-memory cache with LRU and TTL
    new Keyv({
      store: new CacheableMemory({ ttl: 60000, lruSize: 5000 }),
    }),

    //  Redis Store
    new Keyv({
      store: new KeyvRedis('redis://user:pass@localhost:6379'),
    }),
  ],
})

Once it is created, you can use the cache object to set, get, delete, and wrap functions in cache.

// With default ttl and refreshThreshold
const cache = createCache({
  ttl: 10000,
  refreshThreshold: 3000,
})

await cache.set('foo', 'bar')
// => bar

await cache.get('foo')
// => bar

await cache.del('foo')
// => true

await cache.get('foo')
// => null

await cache.wrap('key', () => 'value')
// => value

Using CacheableMemory or lru-cache as storage adapter

Because we are using Keyv, you can use any storage adapter that Keyv supports such as lru-cache or CacheableMemory from Cacheable. Below is an example of using CacheableMemory:

In this example we are using CacheableMemory from Cacheable which is a fast in-memory cache that supports LRU and and TTL expiration.

import { createCache } from 'cache-manager';
import { Keyv } from 'keyv';
import { KeyvCacheableMemory } from 'cacheable';

const store = new KeyvCacheableMemory({ ttl: 60000, lruSize: 5000 });
const keyv = new Keyv({ store });
const cache = createCache({ stores: [keyv] });

Here is an example using lru-cache:

import { createCache } from 'cache-manager';
import { Keyv } from 'keyv';
import { LRU } from 'lru-cache';

const keyv = new Keyv({ store: new LRU({ max: 5000, maxAge: 60000 }) });
const cache = createCache({ stores: [keyv] });

Options

stores?: Keyv[]
List of Keyv instance. Please refer to the Keyv document for more information.
ttl?: number - Default time to live in milliseconds.
The time to live in milliseconds. This is the maximum amount of time that an item can be in the cache before it is removed.
refreshThreshold?: number | (value:T) => number - Default refreshThreshold in milliseconds. You can also provide a function that will return the refreshThreshold based on the value.
If the remaining TTL is less than refreshThreshold, the system will update the value asynchronously in background.
refreshAllStores?: boolean - Default false
If set to true, the system will update the value of all stores when the refreshThreshold is met. Otherwise, it will only update from the top to the store that triggered the refresh.
nonBlocking?: boolean - Default false
If set to true, the system will not block when multiple stores are used. Here is how it affects the type of functions:
- set and mset - will not wait for all stores to finish.
- get and mget - will return the first (fastest) value found.
- del and mdel - will not wait for all stores to finish.
- clear - will not wait for all stores to finish.
- wrap - will do the same as get and set (return the first value found and not wait for all stores to finish).
cacheId?: string - Defaults to random string
Unique identifier for the cache instance. This is primarily used to not have conflicts when using wrap with multiple cache instances.

Methods

set

set(key, value, [ttl]): Promise<value>

Sets a key value pair. It is possible to define a ttl (in milliseconds). An error will be throw on any failed

await cache.set('key-1', 'value 1')

// expires after 5 seconds
await cache.set('key 2', 'value 2', 5000)

See unit tests in test/set.test.ts for more information.

mset

mset(keys: [ { key, value, ttl } ]): Promise<true>

Sets multiple key value pairs. It is possible to define a ttl (in milliseconds). An error will be throw on any failed

await cache.mset([
  { key: 'key-1', value: 'value 1' },
  { key: 'key-2', value: 'value 2', ttl: 5000 },
]);

get

get(key): Promise<value>

Gets a saved value from the cache. Returns a null if not found or expired. If the value was found it returns the value.

await cache.set('key', 'value')

await cache.get('key')
// => value

await cache.get('foo')
// => null

See unit tests in test/get.test.ts for more information.

mget

mget(keys: [key]): Promise<value[]>

Gets multiple saved values from the cache. Returns a null if not found or expired. If the value was found it returns the value.

await cache.mset([
  { key: 'key-1', value: 'value 1' },
  { key: 'key-2', value: 'value 2' },
]);

await cache.mget(['key-1', 'key-2', 'key-3'])
// => ['value 1', 'value 2', null]

ttl

ttl(key): Promise<number | null>

Gets the expiration time of a key in milliseconds. Returns a null if not found or expired.

await cache.set('key', 'value', 1000); // expires after 5 seconds

await cache.ttl('key'); // => the expiration time in milliseconds

await cache.get('foo'); // => null

See unit tests in test/ttl.test.ts for more information.

del

del(key): Promise<true>

Delete a key, an error will be throw on any failed.

await cache.set('key', 'value')

await cache.get('key')
// => value

await cache.del('key')

await cache.get('key')
// => null

See unit tests in test/del.test.ts for more information.

mdel

mdel(keys: [key]): Promise<true>

Delete multiple keys, an error will be throw on any failed.

await cache.mset([
  { key: 'key-1', value: 'value 1' },
  { key: 'key-2', value: 'value 2' },
]);

await cache.mdel(['key-1', 'key-2'])

clear

clear(): Promise<true>

Flush all data, an error will be throw on any failed.

await cache.set('key-1', 'value 1')
await cache.set('key-2', 'value 2')

await cache.get('key-1')
// => value 1
await cache.get('key-2')
// => value 2

await cache.clear()

await cache.get('key-1')
// => null
await cache.get('key-2')
// => null

See unit tests in test/clear.test.ts for more information.

wrap

wrap(key, fn: async () => value, [ttl], [refreshThreshold]): Promise<value>

Wraps a function in cache. The first time the function is run, its results are stored in cache so subsequent calls retrieve from cache instead of calling the function.

If refreshThreshold is set and the remaining TTL is less than refreshThreshold, the system will update the value asynchronously. In the meantime, the system will return the old value until expiration. You can also provide a function that will return the refreshThreshold based on the value (value:T) => number.

await cache.wrap('key', () => 1, 5000, 3000)
// call function then save the result to cache
// =>  1

await cache.wrap('key', () => 2, 5000, 3000)
// return data from cache, function will not be called again
// => 1

// wait 3 seconds
await sleep(3000)

await cache.wrap('key', () => 2, 5000, 3000)
// return data from cache, call function in background and save the result to cache
// =>  1

await cache.wrap('key', () => 3, 5000, 3000)
// return data from cache, function will not be called
// =>  2

await cache.wrap('key', () => 4, 5000, () => 3000);
// return data from cache, function will not be called
// =>  4

await cache.wrap('error', () => {
  throw new Error('failed')
})
// => error

NOTES:

The store that will be checked for refresh is the one where the key will be found first (highest priority).
If the threshold is low and the worker function is slow, the key may expire and you may encounter a racing condition with updating values.
If no ttl is set for the key, the refresh mechanism will not be triggered.

See unit tests in test/wrap.test.ts for more information.

disconnect

disconnect(): Promise<void>

Will disconnect from the relevant store(s). It is highly recommended to use this when using a Keyv storage adapter that requires a disconnect. For each storage adapter, the use case for when to use disconnect is different. An example is that @keyv/redis should be used only when you are done with the cache.

await cache.disconnect();

See unit tests in test/disconnect.test.ts for more information.

Properties

cacheId

cacheId(): string

Returns cache instance id. This is primarily used to not have conflicts when using wrap with multiple cache instances.

stores

stores(): Keyv[]

Returns the list of Keyv instances. This can be used to get the list of stores and then use the Keyv API to interact with the store directly.

const cache = createCache({cacheId: 'my-cache-id'});
cache.cacheId(); // => 'my-cache-id'

See unit tests in test/cache-id.test.ts for more information.

Events

set

Fired when a key has been added or changed.

cache.on('set', ({ key, value, error }) => {
	// ... do something ...
})

del

Fired when a key has been removed manually.

cache.on('del', ({ key, error }) => {
	// ... do something ...
})

clear

Fired when the cache has been flushed.

cache.on('clear', (error) => {
  if (error) {
    // ... do something ...
  }
})

refresh

Fired when the cache has been refreshed in the background.

cache.on('refresh', ({ key, value, error }) => {
  if (error) {
    // ... do something ...
  }
})

See unit tests in test/events.test.ts for more information.

Doing Iteration on Stores

You can use the stores method to get the list of stores and then use the Keyv API to interact with the store directly. Below is an example of iterating over all stores and getting all keys:

import Keyv from 'keyv';
import { createKeyv } from '@keyv/redis';
import { createCache } from 'cache-manager';

const keyv = new Keyv();
const keyvRedis = createKeyv('redis://user:pass@localhost:6379');

const cache = createCache({
  stores: [keyv, keyvRedis],
});

// add some data
await cache.set('key-1', 'value 1');
await cache.set('key-2', 'value 2');

// get the store you want to iterate over. In this example we are using the second store (redis)
const store = cache.stores[1];

if(store?.iterator) {
  for await (const [key, value] of store.iterator({})) {
    console.log(key, value);
  }
}

WARNING: Be careful when using iterator as it can cause major performance issues with the amount of data being retrieved. Also, Not all storage adapters support iterator so you may need to check the documentation for the storage adapter you are using.

Update on redis and ioredis Support

We will not be supporting cache-manager-ioredis-yet or cache-manager-redis-yet in the future as we have moved to using Keyv as the storage adapter @keyv/redis.

Using Legacy Storage Adapters

There are many storage adapters built for cache-manager and because of that we wanted to provide a way to use them with KeyvAdapter. Below is an example of using cache-manager-redis-yet:

import { createCache, KeyvAdapter } from 'cache-manager';
import { Keyv } from 'keyv';
import { redisStore } from 'cache-manager-redis-yet';

const adapter = new KeyvAdapter( await redisStore() );
const cache = createCache({
  stores: [new Keyv({ store: adapter })],
});

This adapter will allow you to add in any storage adapter. If there are issues it needs to follow CacheManagerStore interface.