/**
* 清空购物车商品
*
* @param string $storeId
* @return integer the number of rows deleted
*/
public function clearCartGoods($storeId = null)
{
$condition = ['user_id' => $this->id];
if ($storeId !== null) {
$condition['store_id'] = $storeId;
}
return CartGoods::deleteAll($condition);
}
