use font awesome icon vuetify code example
Example: conditional fontawesome icon vue
<span key="fa-sort-up" v-if="sort && descending"><i class="fas fa-sort-up"></i></span>
<span key="fa-sort-down" v-else-if="sort"><i class="fas fa-sort-down"></i></span>
<span key="fa-sort" v-else><i class="fas fa-sort"></i></span>