@stringsync/vexml/dist/esm/util/lru.js

MusicXML to Vexflow

/**
 * Represents a least-recently-used (LRU) cache.
 *
 * When at capacity, this cache will evict the least recently used key-value pair. This is particularly useful if you
 * don't intend a cache to grow in size indefinitely.
 */
export class LRU {
    capacity;
    map;
    constructor(capacity) {
        this.capacity = capacity;
        this.map = new Map();
    }
    /** Returns the value corresponding to the key, if it exists. Defaults to null. */
    get(key) {
        let value = null;
        if (this.has(key)) {
            value = this.map.get(key);
            this.map.delete(key);
            this.map.set(key, value);
        }
        return value;
    }
    /** Puts the key-value pair, updating how recently "used" a key was used if applicable. */
    put(key, value) {
        if (this.map.has(key)) {
            this.map.delete(key);
        }
        this.map.set(key, value);
        if (this.map.size > this.capacity) {
            const { value } = this.map.entries().next();
            if (typeof value !== 'undefined') {
                this.map.delete(value[0]);
            }
        }
    }
    /** Returns whether the key is in the cache. */
    has(key) {
        return this.map.has(key);
    }
}