@denox/lru_store v1.0.0

LRU Store

This is an LRU Cache implementation using Map as the native Map guarantees the order of the of the key, value pairs to be maintained in the insertion order.

The LRU allows to use anything as key/value just like Map, and it follows the same interface as a Map, with the addition of peek method and maxSize property.

Usage Deno

import LRU from "https://deno.land/x/lru_store/mod.ts";

Usage Node

npm install --save @denox/lru_store

import LRU from "@denox/lru_store";

API

Initialization

The first argument is maxSize and it is required, the second one is entries and it is optional, allowing prepopulating the cache.

const lru = new LRU(100); // Creates an empty LRU Cache with 100 entries capacity
const lruWithData = new LRU(100, [
	["key1", "value1"],
	["key2", "value2"],
]); // Creates an LRU Cache with 2 entries and 100 entries capacity

Set

Add a key/value pair to the cache. If the cache will exceed capacity, it will evict the oldest key/value pair.

lru.set("key", "value");

Get

Retrieve a value from the cache based on the keys, it will return undefined if the key is not found.

lru.get("key");

Peek

Retrieve the value from the cache based on the key, similar with get but without changing the priority of the queue.

// Same behavior as get but without moving the key/value to the end of the eviction queue
lru.peek("key");

Has

Check if a key is inside the LRU, returning true if found or false if not.

lru.has("key");

Delete

Evict the key/value pair based on key, returning true if found or false if not.

lru.delete("key");

Clear

Evict everything from the cache, leaving the LRU empty.

lru.clear();

Size

Get the current size of the LRU.

lru.size; // Number

MaxSize

Get the set capacity of the LRU, size should never exceed maxSize.

lru.maxSize; // Number

Keys, Values, Entries

Get the iterators for keys, values or entries in the eviction order.

Array.from(lru.keys()); // [key1, key2, ...]
Array.from(lru.values()); // [value1, value2, ...]
Array.from(lru.entries()); // [[key1, value1], [key2, value2], ...]

ForEach

Iterate over the LRU entries in the eviction order.

lru.forEach((value, key, lru) => {
	//...
});

License

MIT