Error in nextTick: "TypeError: Cannot read property 'key' of null" v-for报错解决

场景：for循环省市区列表，可以取消重选

问题：取消重选省市区时有时会报错Error in nextTick: "TypeError: Cannot read property 'key' of null"

解决办法：在点击取消时将之前的省/市/区列表清空，猜测可能是因为key值重复导致页面渲染出错