Node module for in memory caching
npm install cache-memoryNode module for in memory caching.
With npm
``bash`
$ npm i cache-memory@3.0.3
`js
const cache = require('cache-memory')
.ttl(60)
.storeUndefinedObjects(false)
.cleanup(60)
.create({ id: 'snacks' });
function standardGetAndSetExample() {
const key = 'the_key1';
let result = cache.get(key);
if (!result) {
cache.set(key, { snack: 'crisps'});
result = cache.get(key);
}
return { value: result, expiry: cache.getExpiry(key) };
}
async function getData() {
return { snack: 'chocolate' };
}
async function getAndSetWithDataRetrievalExample() {
const key = 'the_key2';
let result = await cache.getAndSet(key, getData);
return { value: result, expiry: cache.getExpiry(key) };
}
async function test() {
console.log(Result 1: ${JSON.stringify(standardGetAndSetExample())});Result 2: ${JSON.stringify(await getAndSetWithDataRetrievalExample())}
console.log();
}
test()
.then(() => process.exit(0))
`
Example console output of executed code:
`js`
Result 1: {"value":{"snack":"crisps"},"expiry":"2023-03-24T12:11:07.171Z"}
Result 2: {"value":{"snack":"chocolate"},"expiry":"2023-03-24T12:11:07.176Z"}
Object is used to create cache instances, default configuration variables and scheduled object cleanup.
`js`
const cache = require('cache-memory')
.create([options]);
Creates a new cache instance.
This argument is optional.
- clone: (default: true) Defines whether objects should be cloned when set in and retrieved from cache.id
- : (optional string) The id of the cache. If no id is supplied it will be generated.storeUndefinedObjects
- : (default: false) Defines whether undefined objects should be stored in memory.ttl
- : (default: 0) Defines in seconds how long an object should be stored in memory.0
= Foreverhit
- : Function called every time an object is retrieved from cache.miss
- : Function called every time an object is not from cache.added
- : Function called every time an object is added to cache.removed
- : Function called every time an object is removed from cache.count
- : Function called every time an object is added or removed from cache.
** hit, miss, added, removed functions are all called with the following object structure.
`js`
{
id: 'some-id',
key: 'some-key'
}
** count function is called with the following object structure.
`js`
{
id: 'some-id',
count: 123
}
`js`
require('cache-memory')
.clone(false);
Turns off object cloning (default true).
`js`
require('cache-memory')
.storeUndefinedItems(true);
Allows undefined objects to be stored in cache (default false).
`js`
require('cache-memory')
.ttl(true);
Defines in seconds how long an object should be stored in memory.
`js`
require('cache-memory')
.cleanup(60);
Forces expired objects to be removed from cache every 60 seconds. By default no cleanup is performed.
`js`
require('cache-memory')
.clear();
Clears the in memory cache of all active cache instances.
`js`
const cachers = require('cache-memory').cachers();
Gets all active cache instances.
`js`
const cacher = require('cache-memory').cacher('snacks');
Gets an active cacher by it's id.
`js`
const stats = require('cache-memory').stats();
Gets an array of stats across all active cachers.
`js`
[
{
id: '1',
stats: {
count: 5,
hits: 17123,
misses: 57,
hitRate: 0.9966821885913854
}
}
]
`js`
require('cache-memory').dispose();
Clears all in memory cacher instances and also clears the cleanup task if defined using the cleanup function.
It's functions are defined below.
`js`
const obj = cache.get(key, [options]);
Gets an object from cache, undefined will be returned if object does not exist.
This argument is optional.
- clone: (default: true) Defines whether objects should be cloned when set in and retrieved from cache.id
- : The id of the cacher (string value).storeUndefinedObjects
- : (default: false) Defines whether undefined objects should be stored in memory.ttl
- : (default: 0) Defines in seconds how long an object should be stored in memory.0
= Foreverhit
- : (optional) Function called every time an object is retrieved from cache.miss
- : (optional) Function called every time an object is not from cache.added
- : (optional) Function called every time an object is added to cache.removed
- : (optional) Function called every time an object is removed from cache.count
- : (optional) Function called every time an object is added or removed from cache.
** hit, miss, added, removed functions are all called with the following object structure.
`js`
{
id: 'some-id',
key: 'some-key'
}
** count function is called with the following object structure.
`js`
{
id: 'some-id',
count: 123
}
`js`
const expiry = cache.getExpiry(key);
Gets the expiry DateTime of an object in cache, undefined is returned if object is not found.
`js`
cache.set(key, value, [options]);
Stores an object in cache.
This argument is optional.
- storeUndefinedObjects: (default: global or instance level definition) Defines whether undefined objects should be stored in memory.ttl
- : (default: global or instance level definition) Defines in seconds how long an object should be stored in memory.0
= Forever
If 'storeUndefinedObjects' is false. undefined, null and objects with an IsNull function that returns true will not be stored.
`js
async function getter() {
return 'hello-world-' + Math.random(0, 100);
}
await cache.getAndSet(key, getter, [options]);
`
Gets and sets an object in cache. The getAndSet function is an async function so should be awaited. It can also refresh its data in the background.
This argument is optional.
- storeUndefinedObjects: (default: global or instance level definition) Defines whether undefined objects should be stored in memory.ttl
- : (default: global or instance level definition) Defines in seconds how long an object should be stored in memory.0
= ForeverrefreshIntervalInMilliseconds
- : (optional) Defines whether the cache should be refreshed using the getter every so many milliseconds.refreshIntervalWhenRefreshFailsInMilliseconds
- : (optional) If refreshIntervalInMilliseconds is set and a failure occurs when refreshing the cache the refresh delay will change to refreshIntervalWhenRefreshFailsInMilliseconds if set otherwise refreshIntervalInMilliseconds.
`js`
cache.clear();
Removes all objects from the cache instance.
`js`
cache.remove(key);
Remove the object from cache.
`js`
const stats = cache.stats();
Gets the stats for the cache instance.
Example return value:
`js`
{
count: 5,
hits: 17123,
misses: 57,
hitRate: 0.9966821885913854
}
`js`
const keys = cache.keys();
Gets all keys for objects stored in the cache instance.
`js`
const options = cache.options();
Gets all configured options for a cache instance.
Example return value:
`js``
{
ttl: 60,
clone: true,
storeUndefinedObjects: false
}
(MIT)
Copyright (c) 2023 Lee Crowe
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