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);
const lruWithData = new LRU(100, [
["key1", "value1"],
["key2", "value2"],
]);
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.
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;
MaxSize
Get the set capacity of the LRU, size
should never exceed maxSize
.
lru.maxSize;
Keys, Values, Entries
Get the iterators for keys
, values
or entries
in the eviction order.
Array.from(lru.keys());
Array.from(lru.values());
Array.from(lru.entries());
ForEach
Iterate over the LRU entries in the eviction order.
lru.forEach((value, key, lru) => {
});
License
MIT