code: function extractComponentId() {
    var event = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
  
    var _ref = event.currentTarget || {},
        componentId = _ref.dataset.componentId;
  
    return componentId;
  }
docs: 从事件对象中解析得到 componentId 需要在元素上声明 data-component-id