@uploadx/core/lib/utils/cache.js

Node.js resumable upload middleware

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Cache = void 0;
/**
 * Time-aware LRU Cache Implementation
 */
class Cache {
    /**
     * @param maxEntries - The maximum number of entries before the cache starts flushing out the old items
     * @param maxAge - The maximum life of a cached items in seconds
     */
    constructor(maxEntries = 1000, maxAge) {
        this.maxEntries = maxEntries;
        this.maxAge = maxAge;
        this._map = new Map();
        this._ttl = maxAge ? maxAge * 1000 : 0;
    }
    /**
     * @returns the total number of cache entries, including expired ones
     */
    get size() {
        return this._map.size;
    }
    /**
     * Cache keys iterator
     * @returns an iterator of all keys in a cache
     */
    keys() {
        return this._map.keys();
    }
    /**
     * Remove expired entries
     * @returns array of actual keys
     */
    prune() {
        if (this._ttl) {
            const now = Date.now();
            for (const [key, [, expiresAt]] of this._map) {
                if (now > expiresAt)
                    this._map.delete(key);
            }
        }
        while (this._map.size > this.maxEntries) {
            this._map.delete(this._map.keys().next().value);
        }
        return Array.from(this._map.keys());
    }
    clear() {
        this._map.clear();
    }
    /**
     * Get an item from the cache
     * @param key - The key to look up
     * @returns The cached value or undefined if it is not found or expired
     */
    get(key) {
        const tuple = this._map.get(key);
        if (!tuple)
            return;
        this._map.delete(key);
        if (this._ttl) {
            const now = Date.now();
            if (now > tuple[1])
                return;
            tuple[1] = now + this._ttl;
        }
        this._map.set(key, tuple);
        return tuple[0];
    }
    /**
     * Check if the item exists and has not expired
     * @param key - The key to look up
     */
    has(key) {
        const tuple = this._map.get(key);
        if (!tuple)
            return false;
        if (this._ttl) {
            if (Date.now() > tuple[1]) {
                this._map.delete(key);
                return false;
            }
        }
        return true;
    }
    /**
     * Add the new key and value to the cache
     * @param key - The key to store the value under
     * @param value - The value to be stored in the cache
     * @returns The value that was set
     */
    set(key, value) {
        if (this._map.size === this.maxEntries)
            this._map.delete(this._map.keys().next().value);
        const expiresAt = this._ttl ? Date.now() + this._ttl : 0;
        this._map.set(key, [value, expiresAt]);
        return value;
    }
    /**
     * Delete the key from the cache
     * @param key - The key of the item to remove from the cache
     */
    delete(key) {
        return this._map.delete(key);
    }
}
exports.Cache = Cache;