class EventBus {
  constructor() {
    this._eventContainer = {};
  }
  // 添加监听事件
  on(type, fn) {
    this._eventContainer[type] = this._eventContainer[type] || [];
    this._eventContainer[type].push(fn);
    return this;
  }

  // 删除监听事件
  off(type, fn) {
    if(this._eventContainer[type]) {
      let index = this._eventContainer[type].indexOf(fn);
      index >=0 && this._eventContainer[type].splice(index, 1);
    }
    return this;
  }

  // 触发监听事件
  trigger(type, ...args) {
    if (type && this._eventContainer[type]) {
      [...this._eventContainer[type]].forEach((fn)=> {
        fn.apply(null, args);
      })
    }
    return this;
  }

  // reset
  reset() {
    this._eventContainer = {};
  }
}

const eventBus = new EventBus();

export default eventBus;