@aurios/jason/dist/data/cache.js

A simple, lightweight, and embeddable JSON document database built on Bun.

export default class Cache {
    #data = new Map();
    #queue = [];
    #timeout = 60000;
    #maxSize;
    #cleanupTimer;
    constructor(cacheTimout = 60_000, maxSize = 1000) {
        this.#timeout = cacheTimout;
        this.#maxSize = maxSize;
        this.#cleanupTimer = setInterval(() => this.#cleanup(), Math.min(30_000, this.#timeout));
    }
    /**
     * Gets the current cache timeout duration.
     * Defaults to 60 seconds (1 minute).
     * @returns The duration in milliseconds after which cached items are automatically removed.
     */
    get timeout() {
        return this.#timeout;
    }
    /**
     * Sets the cache timeout duration.
     *
     * @param timeout - The duration in milliseconds after which the cached item should be removed.
     */
    set timeout(timeout) {
        this.#timeout = timeout;
    }
    /**
     * Updates the cache with the given id and value.
     *
     * If the cache has reached its maximum size, it will remove 10% of the items
     * in the cache before adding the new item.
     *
     * @param id - The id of the item to be updated.
     * @param value - The value of the item to be updated.
     */
    update(id, value) {
        if (this.#data.has(id)) {
            const entry = this.#data.get(id);
            if (!entry)
                return;
            entry.value = value;
            entry.timestamp = this.#getNow();
            this.#refresh(id);
        }
        else {
            if (this.#data.size >= this.#maxSize) {
                this.#evict(Math.floor(this.#maxSize * 0.1));
            }
            this.#data.set(id, { value, timestamp: this.#getNow() });
            this.#queue.push(id);
        }
    }
    /**
     * Retrieves an item from the cache by its id.
     *
     * If the item is not found or has exceeded the cache timeout, it returns null.
     * Otherwise, it returns the cached value.
     *
     * @param id - The id of the item to retrieve from the cache.
     * @returns The cached value, or null if not found or expired.
     */
    get(id) {
        const entry = this.#data.get(id);
        if (!entry)
            return null;
        const now = this.#getNow();
        if (now - entry.timestamp > this.#timeout) {
            this.#data.delete(id);
            return null;
        }
        this.#refresh(id);
        return entry.value;
    }
    /**
     * Removes the item with the specified id from the cache.
     *
     * @param id - The id of the item to be removed from the cache.
     */
    delete(id) {
        this.#data.delete(id);
    }
    /**
     * Destroys the cache by stopping the automatic cleanup interval.
     *
     * Use this method when you are finished with the cache.
     */
    destroy() {
        clearInterval(this.#cleanupTimer);
    }
    #refresh(id) {
        const idx = this.#queue.indexOf(id);
        if (idx > -1) {
            this.#queue.splice(idx, 1);
        }
        this.#queue.push(id);
    }
    #evict(count) {
        const victims = this.#queue.splice(0, count);
        for (const id of victims) {
            this.#data.delete(id);
        }
    }
    #cleanup() {
        const now = this.#getNow();
        const threshold = now - this.#timeout;
        for (const [id, entry] of this.#data) {
            if (entry.timestamp < threshold) {
                this.#data.delete(id);
            }
        }
    }
    #getNow = Date.now.bind(Date);
}