mhmood-sf / CachedKeyv

Keyv with caching - hence the name.

This is an extension of Keyv. CachedKeyv uses a simple in-memory cache to store and serve data significantly faster during runtime. Actual database operations are queued up behind-the-scenes.

Quick guide

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CachedKeyv exposes the same get/set/delete API exposed by Keyv, with the same parameters and usage.

// Import Keyv
const CachedKeyv = require('./CachedKeyv.js');

// And then one of the following
const keyv = new CachedKeyv();
const keyv = new CachedKeyv('uri');
const keyv = new CachedKeyv(options);
const keyv = new CachedKeyv('uri', options);

However, creating instances of CachedKeyv is slightly different from Keyv, since CachedKeyv can take options for both the internal database and the internal cache used. See API for more.

// Example of an options object for CachedKeyv
const options = {
    db: {
        uri: 'someURI',
        namespace: 'myNamespace',
        ttl: 1000 * 60 * 10,
        serialize: JSON.stringify,
        deserialize: JSON.parse,
        store: new Map(),
        adapter: 'someAdapter'
    },
    cache: {
        ttl: 1000 * 60 * 10
    }
};

Since CachedKeyv has two instances of Keyv running (one for the persistent db and one for the cache), a simple shorthand for attaching/detaching listeners to them is provided. See API for more.

// Attach listeners
keyv.on('db', 'error', console.log);      // Attaches listener to only db
keyv.on('cache', 'error', console.log);   // Attaches listener to only cache
keyv.on('error', console.log);            // Attaches listener to both db and cache

API

---

new CachedKeyv([uri], [options])

Returns a CachedKeyv instance.

uri

Type: String Default: undefined

The connection string uri. This is merged into the options object as options.db.uri, rather than options.uri (as done in Keyv)

options

Type: object

This options object contains options for both the internal db and internal cache (both instances of Keyv). As such, options.db is passed to the internal Keyv instance for the persistent database, while options.cache is passed to the Keyv instance for the cache.

options.db

Type: object

This is the same as the options that Keyv accepts, documented here. This is passed on to the internal Keyv instance for the persistent database.

options.cache

Type: object

This object contains options for the internal cache. Currently, it only takes one option.

options.cache.ttl

Type: number

Number specifying the default time-to-live expiry for the cache. This can be overriden by the set method for CachedKeyv instances.

Instance

The CachedKeyv instances expose the same get/set/delete/clear API that Keyv exposes. See here for more.

on([emitter], event, listener)

Shorthand for attaching listeners to either the internal db, cache, or both.
Example:

// Attach listeners
keyv.on('db', 'error', console.log);      // Attaches listener to only db
keyv.on('cache', 'error', console.log);   // Attaches listener to only cache
keyv.on('error', console.log);            // Attaches listener to both db and cache

off([emitter], event, listener)

Shorthand for detaching listeners from either the internal db, cache, or both.
Example:

// Detach listeners
keyv.off('db', 'error', console.log);      // Detaches listener from only db
keyv.off('cache', 'error', console.log);   // Detaches listener from only cache
keyv.off('error', console.log);            // Detaches listener from both db and cache