@homeofthings/node-utils/src/lib/lru-cache/lru-cache.js

HomeOfThings - Node Utils: various utilities and common types

"use strict";
/* eslint-disable @typescript-eslint/no-unused-vars */
Object.defineProperty(exports, "__esModule", { value: true });
exports.LruCache = void 0;
class LruCache {
    _maxEntries;
    // NOTE: javascript Map remembers the original insertion order
    _map = new Map();
    get maxEntries() {
        return this._maxEntries;
    }
    set maxEntries(newMaxEntries) {
        this._maxEntries = Math.max(newMaxEntries, 0);
        this.resize(this._maxEntries);
    }
    get size() {
        return this._map.size;
    }
    constructor(_maxEntries = 20) {
        this._maxEntries = _maxEntries;
    }
    get(key) {
        let item = undefined;
        if (this._map.has(key)) {
            // mark item as least recently used
            item = this._map.get(key);
            this._map.delete(key);
            this._map.set(key, item);
        }
        return item;
    }
    set(key, item) {
        if (!this.delete(key)) {
            this.resize(this._maxEntries - 1);
        }
        this.onInsert(item);
        this._map.set(key, item);
    }
    has(key) {
        return this._map.has(key);
    }
    delete(key) {
        const item = this._map.get(key);
        if (item) {
            this.onDelete(item);
        }
        return this._map.delete(key);
    }
    onInsert(_item) { }
    onDelete(_item) { }
    resize(newSize) {
        while (this._map.size > newSize) {
            this.delete(this._map.keys().next().value);
        }
    }
}
exports.LruCache = LruCache;
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