Simple and fast NodeJS internal caching.

Forked from node-cache great work by Josh Gwosdz, M. Peter, Daniel Luft and others.

A simple caching module that has set, get and delete methods and works a little bit like memcached. Keys can have a timeout (ttl) after which they expire and are deleted from the cache. All keys are stored in a single object so the practical limit is at around 1m keys.

We took 5.1.2 rewriten it to TypeScript and added high performance options in separate class

BREAKING CHANGES since node-cache

Although not breaking per definition, our typescript rewrite changed internal function.

Cache is not suporting useClones option set to true with functions as values. Use NodeCacheTs to achive similar or better effect.

Install

	npm install node-cache-ts --save

Examples:

Initialize (INIT):

const { NodeCache } = require( "node-cache-ts" );
const myCache = new NodeCache();

Options

• stdTTL: (default: 0) the standard ttl as number in seconds for every generated cache element. 0 = unlimited
• checkperiod: (default: 600) The period in seconds, as a number, used for the automatic delete check interval. 0 = no periodic check.
• useClones: (default: true) en/disable cloning of variables. If true you'll get a copy of the cached variable. If false you'll save and get just the reference.
  Note:
  • true is recommended if you want simplicity, because it'll behave like a server-based cache (it caches copies of plain data).
  • false is recommended if you want to achieve performance or save mutable objects or other complex types with mutability involved and wanted, because it'll only store references of your data.
  • Here's a simple code example showing the different behavior
• deleteOnExpire: (default: true) whether variables will be deleted automatically when they expire. If true the variable will be deleted. If false the variable will remain. You are encouraged to handle the variable upon the event expired by yourself.
• maxKeys: (default: -1) specifies a maximum amount of keys that can be stored in the cache. If a new item is set and the cache is full, an error is thrown and the key will not be saved in the cache. -1 disables the key limit.

NodeCache:

import { NodeCache } from 'node-cache-ts';
const stringCache = new NodeCache<string>( { stdTTL: 100, checkperiod: 120 } );

NodeCacheTs:

import NodeCacheTs from 'node-cache-ts';
const myServiceCache = new NodeCacheTs<{key: string}, string>( { stdTTL: 100 }, async (args: { name: string }): Promise<string> => {
    return await myServiceCall(args.name);
} );

const myResult = myServiceCache.call('key', { 'John' });

or if you don't like types:

import { NodeCacheTs } from 'node-cache-ts';
const myServiceCache = new NodeCacheTs( { stdTTL: 100 }, async ( args ) => {
    return await myServiceCall(args);
} );

const myResult = myServiceCache.call('key', { 'John' });

NodeCacheTs is generally quicker and more resilent to errors see result of our tests.

|NodeCache|NodeCacheTs| |:--:|:--:| || |

Beware on the lateny graph scale is not linear

Here the test for the flaky service throwing error code 500 with probability of 1%:

|NodeCache|NodeCacheTs| |:--:|:--:| ||

Errors disapear in second phase of the tests as subsequent calls are repeated in case of error and the chance of error reachng to customer is very low.

And data is refreshed in the same phase. However number of calls to the server is significantly lower. Due to the fact that SnowCashe will call the server only for cached arguments and NodeCache will call as many times as many threads ask for same inforation and no data is in the cache.

Only in NodeCacheTs (rest is inherited from NodeCache):

myCache.call( key, { arg1 } )

Cache will call a method past during construction and cache both it's result and arguments for that method under the key. Both arguments and result well be selialized unless option.argsUseClones is set to false.

Method will return the value if it is cached from the cache if it is not cached from the method past during construction. Method will be called again after ttr passes with first arguments for the given key. When after ttr the call method is used arguments will be remembered again and used in next call.

If the method called in the backround returns an error the method will be called again if stdTTL is not reached. On error refresh_error event will be emited remember to catch it and log it or act upon it.

const myResult = myServiceCache.call('key', { 'John' });

Store a key (SET):

myCache.set( key, val, [ ttl ] )

Sets a key value pair. It is possible to define a ttl (in seconds). Returns true on success.

Key-validation: The keys can be given as either string or number, but are casted to a string internally anyway. All other types will throw an error.

obj = { my: "Special", variable: 42 };

success = myCache.set( "myKey", obj, 10000 );
// true

Note: If the key expires based on it's ttl it will be deleted entirely from the internal data object.

Store multiple keys (MSET):

myCache.mset(Array<{key, val, ttl?}>)

Sets multiple key val pairs. It is possible to define a ttl (seconds). Returns true on success.

const obj = { my: "Special", variable: 42 };
const obj2 = { my: "other special", variable: 1337 };

const success = myCache.mset([
	{key: "myKey", val: obj, ttl: 10000},
	{key: "myKey2", val: obj2},
])

Retrieve a key (GET):

myCache.get( key )

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

value = myCache.get( "myKey" );
if ( value == undefined ){
	// handle miss!
}
// { my: "Special", variable: 42 }

Since 2.0.0:

The return format changed to a simple value and a ENOTFOUND error if not found *( as result instance of Error )

Since 2.1.0:

The return format changed to a simple value, but a due to discussion in #11 a miss shouldn't return an error. So after 2.1.0 a miss returns undefined.

Take a key (TAKE):

myCache.take( key )

get the cached value and remove the key from the cache.
Equivalent to calling get(key) + del(key).
Useful for implementing single use mechanism such as OTP, where once a value is read it will become obsolete.

myCache.set( "myKey", "myValue" )
myCache.has( "myKey" ) // returns true because the key is cached right now
value = myCache.take( "myKey" ) // value === "myValue"; this also deletes the key
myCache.has( "myKey" ) // returns false because the key has been deleted

Get multiple keys (MGET):

myCache.mget( [ key1, key2, ..., keyn ] )

Gets multiple saved values from the cache. Returns an empty object {} if not found or expired. If the value was found it returns an object with the key value pair.

value = myCache.mget( [ "myKeyA", "myKeyB" ] );
/*
	{
		"myKeyA": { my: "Special", variable: 123 },
		"myKeyB": { the: "Glory", answer: 42 }
	}
*/

Since 2.0.0:

The method for mget changed from .get( [ "a", "b" ] ) to .mget( [ "a", "b" ] )

Delete a key (DEL):

myCache.del( key )

Delete a key. Returns the number of deleted entries. A delete will never fail.

value = myCache.del( "A" );
// 1

Delete multiple keys (MDEL):

myCache.del( [ key1, key2, ..., keyn ] )

Delete multiple keys. Returns the number of deleted entries. A delete will never fail.

value = myCache.del( "A" );
// 1

value = myCache.del( [ "B", "C" ] );
// 2

value = myCache.del( [ "A", "B", "C", "D" ] );
// 1 - because A, B and C not exists

Change TTL (TTL):

myCache.ttl( key, ttl )

Redefine the ttl of a key. Returns true if the key has been found and changed. Otherwise returns false. If the ttl-argument isn't passed the default-TTL will be used.

The key will be deleted when passing in a ttl < 0.

myCache = new NodeCache( { stdTTL: 100 } )
changed = myCache.ttl( "existentKey", 100 )
// true

changed2 = myCache.ttl( "missingKey", 100 )
// false

changed3 = myCache.ttl( "existentKey" )
// true

Get TTL (getTTL):

myCache.getTtl( key )

Receive the ttl of a key. You will get:

• undefined if the key does not exist
• 0 if this key has no ttl
• a timestamp in ms representing the time at which the key will expire

myCache = new NodeCache( { stdTTL: 100 } )

// Date.now() = 1456000500000
myCache.set( "ttlKey", "MyExpireData" )
myCache.set( "noTtlKey", "NonExpireData", 0 )

ts = myCache.getTtl( "ttlKey" )
// ts wil be approximately 1456000600000

ts = myCache.getTtl( "ttlKey" )
// ts wil be approximately 1456000600000

ts = myCache.getTtl( "noTtlKey" )
// ts = 0

ts = myCache.getTtl( "unknownKey" )
// ts = undefined

List keys (KEYS)

myCache.keys()

Returns an array of all existing keys.

mykeys = myCache.keys();

console.log( mykeys );
// [ "all", "my", "keys", "foo", "bar" ]

Has key (HAS)

myCache.has( key )

Returns boolean indicating if the key is cached.

exists = myCache.has( 'myKey' );

console.log( exists );

Statistics (STATS):

myCache.getStats()

Returns the statistics.

myCache.getStats();
	/*
		{
			keys: 0,    // global key count
			hits: 0,    // global hit count
			misses: 0,  // global miss count
			ksize: 0,   // global key size count in approximately bytes
			vsize: 0    // global value size count in approximately bytes
		}
	*/

Flush all data (FLUSH):

myCache.flushAll()

Flush all data.

myCache.flushAll();
myCache.getStats();
	/*
		{
			keys: 0,    // global key count
			hits: 0,    // global hit count
			misses: 0,  // global miss count
			ksize: 0,   // global key size count in approximately bytes
			vsize: 0    // global value size count in approximately bytes
		}
	*/

Flush the stats (FLUSH STATS):

myCache.flushStats()

Flush the stats.

myCache.flushStats();
myCache.getStats();
	/*
		{
			keys: 0,    // global key count
			hits: 0,    // global hit count
			misses: 0,  // global miss count
			ksize: 0,   // global key size count in approximately bytes
			vsize: 0    // global value size count in approximately bytes
		}
	*/

Close the cache:

myCache.close()

This will clear the interval timeout which is set on check period option.

myCache.close();

Events

refresh_error (NodeCacheTs only)

On error refresh_error event will be emited remember to catch it and log it or act upon it.

myCache.on( "set", function( error, key, args) ){
	// ... do something ...
	console.log(error); //or something similar
});

set

Fired when a key has been added or changed. You will get the key and the value as callback argument.

myCache.on( "set", function( key, value ){
	// ... do something ...
});

del

Fired when a key has been removed manually or due to expiry. You will get the key and the deleted value as callback arguments.

myCache.on( "del", function( key, value ){
	// ... do something ...
});

expired

Fired when a key expires. You will get the key and value as callback argument.

myCache.on( "expired", function( key, value ){
	// ... do something ...
});

flush

Fired when the cache has been flushed.

myCache.on( "flush", function(){
	// ... do something ...
});

flush_stats

Fired when the cache stats has been flushed.

myCache.on( "flush_stats", function(){
	// ... do something ...
});

Re-run the performance tests

In separate terminals run:

npm run compile-watch this will watch for your changes

cd test; docker-compose up this will start grafana and influxdb

npm run mock-server-watch this will watch for your changes

cd ./test/
docker-compose run k6 run /scripts/load.k6.js

The catalogue is from docker.

Now click this link http://localhost:3000/dashboards select prefered dashboard and enjoy the show refresh is an icon in right upper conrner . You can change scerios to ones commented out in the ./test/load.k6.js.

Compatibility

node-cache-ts supports all node versions >= 8 (check!!!)

Release History

|Version|Date|Description| |:--:|:--:|:--| |1.0.0|2024-03-01|Fork from node_cache TS rewrite and NodeCacheTs added.|

Other projects

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The MIT License (MIT)

Copyright © 2024 Jan Topinski and the node-cache maintainers, https://github.com/node-cache/node-cache

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.