how can get index & count in vuejs

you can just add 1

<li v-for="(catalog, itemObjKey) in catalogs">this index : {{itemObjKey + 1}}</li>

to get the length of an array/objects

{{ catalogs.length }}

In case, your data is in the following structure, you get string as an index

items = {
   am:"Amharic",
   ar:"Arabic",
   az:"Azerbaijani",
   ba:"Bashkir",
   be:"Belarusian"
}

In this case, you can use extra variable to get the index in number:

<ul>
  <li v-for="(item, key, index) in items">
    {{ item }} - {{ key }} - {{ index }}
  </li>
</ul>

Source: https://alligator.io/vuejs/iterating-v-for/