class State {
  /**
   * @type {string}
   */
  language = 'ja';

  /**
   * @type {number}
   */
  turn = 0;

  /**
   * @type {number}
   */
  money = 0;

  /**
   * @type {Monster[]}
   */
  monsters = [];

  /**
   * @type {Trainer}
   */
  player = null;

  /**
   * @type {Trainer}
   */
  opponent = null;

  /**
   * @type {Technique}
   */
  activeTechnique = null;
};