In order to track each node’s identity, and thus reuse and reorder existing elements, you need to provide a unique key attribute for each item with in v-for iteration. An ideal value for key would be the unique id of each item. Let us take an example usage,
<div v-for="item in items" :key="item.id">
Hence, It is always recommended to provide a key with v-for whenever possible, unless the iterated DOM content is simple. Note: You shouldn’t use non-primitive values like objects and arrays as v-for keys. Use string or numeric values instead.