Cache

Implements: Store, Serializable

Source: cache.js:53

A tiny in-memory, least-recently-used (LRU) cache.

This class is the showcase's centerpiece: its members exercise nearly every member-level tag the theme renders — parameters, returns, examples, events, deprecation, modifiers, and cross-references.

A Cache is not thread-safe across workers. Wrap shared access in a Queue if you need ordered writes.

Eviction follows a strict recency order:

Example

Basic usage

const cache = new Cache({ maxSize: 2 });
cache.set('a', 1).set('b', 2);
cache.get('a'); // => 1, and 'a' is now most-recently-used

• Since: 1.0.0
• Version: 1.2.0
• Author: The clean-jsdoc-theme team
• See:
  • CacheOptions
  • createCache for a one-shot factory

Constructor

new Cache([options])

Create a new cache.

Parameters

• options (CacheOptions, optional, default: "{}") — Configuration for the cache.
  • options.maxSize (number, optional, default: 100) — Max entries before eviction.
  • options.ttl (number, optional, default: 0) — Per-entry time-to-live in ms.

Instance Methods

set(key, value) -> Cache

Implements: Store#set

Store a value under a key. If the cache is full, the least-recently-used entry is evicted first and a evict event fires.

Parameters

• key (string) — The key to store the value under.
• value (*) — The value to cache.

Returns

• Cache — The cache instance, for chaining.

Fires

• Cache#event:evict

Example

Calls chain

cache.set('user:1', { name: 'Ada' }).set('user:2', { name: 'Linus' });

get(key) -> *

Implements: Store#get

Look up a value by key, marking it as recently used.

Parameters

• key (string) — The key to look up.

Returns

• * — The cached value, or undefined if the key is not present.

has(key) -> boolean

Check whether a key is present without affecting its recency.

Parameters

• key (string) — The key to test.

Returns

• boolean — true if the key is cached.

remove(key) -> boolean

Remove a single entry.

Since 1.2.0 — prefer Cache#clear or let entries expire via `ttl`. This method will be removed in 2.0.

Parameters

• key (string) — The key to remove.

Returns

• boolean — true if an entry was removed.

clear() -> void

Remove every entry from the cache.

Returns

• void

toJSON() -> Object.<string, *>

Implements: Serializable#toJSON

Serialize the cache to a plain object — satisfies Serializable.

Returns

• Object.<string, *> — A snapshot of every entry.

Instance Fields

maxSize

The maximum number of entries this cache will hold.

Type

number

ttl

Time-to-live per entry, in milliseconds. 0 means entries never expire.

Type

number

size

The number of entries currently stored.