[Vuejs]-With VUE – is the HTML update even if only part of it is different?

https://v2.vuejs.org/v2/guide/list.html

To give Vue a hint so that it can track each node’s identity, and thus reuse and reorder existing elements, you need to provide a unique key attribute for each item:

<div v-for="item in items" v-bind:key="item.id">