class JsStorage { constructor() { this.db = {}; } get(key) { return this.db[key]; } get_or_element(key, defaultElement) { const element = this.db[key]; if (element === undefined) { return defaultElement; } else { return element } } put(key, value) { this.db[key] = value; } del(key) { delete this.db[key]; } put_batch(key_values) { key_values.forEach(element => { this.db[element.key] = element.value; }); } } module.exports = JsStorage;