lrufy/dist/linked-list.js

A feature-rich LRU cache implementation with TTL support, custom sizing, and event hooks

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.DoublyLinkedList = exports.Node = void 0;
/**
 * Represents a node in a doubly linked list
 */
class Node {
    /**
     * Creates a new node
     * @param key - The key associated with this node
     * @param value - The value stored in this node
     */
    constructor(key, value) {
        this.prev = null;
        this.next = null;
        this.size = 0;
        this.expiry = null;
        this.key = key;
        this.value = value;
    }
}
exports.Node = Node;
/**
 * A doubly linked list implementation to track LRU order
 */
class DoublyLinkedList {
    constructor() {
        this.head = null;
        this.tail = null;
        this.length = 0;
    }
    /**
     * Adds a node to the front of the list (most recently used)
     * @param node - The node to add
     * @returns The added node
     */
    addToFront(node) {
        if (!this.head) {
            this.head = node;
            this.tail = node;
        }
        else {
            node.next = this.head;
            this.head.prev = node;
            this.head = node;
        }
        this.length++;
        return node;
    }
    /**
     * Removes a node from the list
     * @param node - The node to remove
     * @returns The removed node
     */
    remove(node) {
        if (node.prev) {
            node.prev.next = node.next;
        }
        else {
            this.head = node.next;
        }
        if (node.next) {
            node.next.prev = node.prev;
        }
        else {
            this.tail = node.prev;
        }
        node.prev = null;
        node.next = null;
        this.length--;
        return node;
    }
    /**
     * Moves a node to the front of the list (marks as recently used)
     * @param node - The node to move to the front
     * @returns The moved node
     */
    moveToFront(node) {
        if (this.head === node) {
            return node;
        }
        this.remove(node);
        return this.addToFront(node);
    }
    /**
     * Removes the least recently used node (from the tail)
     * @returns The removed node or null if the list is empty
     */
    removeTail() {
        if (!this.tail)
            return null;
        return this.remove(this.tail);
    }
    /**
     * Clears the linked list
     */
    clear() {
        this.head = null;
        this.tail = null;
        this.length = 0;
    }
}
exports.DoublyLinkedList = DoublyLinkedList;