BunCache

Pluggable in-memory cache with swappable eviction policies.

API

Cache<K, V>

In-memory key-value cache with a fixed maximum size and an optional eviction policy.

Constructor

new Cache<K, V>(maxSize?, policy?)

Argument	Type	Default	Description
maxSize	number	Infinity	Maximum number of entries. When full, eviction runs.
policy	object	NoEviction	Eviction policy implementing the policy interface.

Methods

• get(key: K): V | undefined
  Returns the value for key, or undefined if missing.

• set(key: K, value: V): void
  Stores value under key.

• delete(key: K): void
  Removes key from the cache.

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Eviction policies

Policies live under src/eviction/. You can use a built-in one or implement the same interface for a custom policy.

Built-in policies

Policy	Import	Behavior
LRU	./src/eviction/lru	Evicts the least recently used key. Good default for most caches.
LFU	./src/eviction/lfu	Evicts the least frequently used key. Good when access frequency matters more than recency.
Random	./src/eviction/random	Evicts a random key. Simple and fast; no access tracking.
NoEviction	./src/eviction/none (default)	Never evicts (evict() returns null). When at capacity, set does nothing for new keys.

Using a policy

import { Cache } from "./src/index";
import { LRU } from "./src/eviction/lru";
import { LFU } from "./src/eviction/lfu";
import { Random } from "./src/eviction/random";

// LRU: drop least recently used when full
const lruCache = new Cache(100, new LRU<string>());

// LFU: drop least frequently used when full
const lfuCache = new Cache(100, new LFU<string>());

// Random: drop a random key when full
const randomCache = new Cache(100, new Random<string>());

// No eviction (default): unbounded or reject new keys when at maxSize
const noEvictionCache = new Cache(100); // or new Cache(100, new NoEviction())