Vue項目，運行出現warning(Emitted value instead of an instance of Error)

組件：<XXXX v-for="item in items" />

warning：(Emitted value instead of an instance of Error) <XXXX v-for="item in items" />: component lists rendered with v-for should have explicit keys.

See https://vuejs.org/guide/list.html#key for more info.

解決方式：在組件中加入自定義的屬性key值就好

<XXXX v-for="item in items" :key="item" />