如何在量角器动态时找到'datepicker'实例

When i'm trying to locate 'datepicker' in protractor, i found every time a new date the instance/object of 'datepicker' created with same class='.datepicker' with incremented value of z-index, but i want to handle the single object or at least old object/instance should get destroyed to locate new object.When i'm trying to locate 'datepicker' in protr