how change font aswome class in new vwesion in vue code example

Example 1: installing fontawesome vue project

//install fontawesome icons
npm install --save-dev @fortawesome/fontawesome-free

//inside main.js add
import '@fortawesome/fontawesome-free/css/all.css'     <------
import '@fortawesome/fontawesome-free/js/all.js'    <------
.
.
.
new Vue({  router,  store,  render: h => h(App),}).$mount('#app')


// you can now use the icons anywhere in your project with the <i>
   <i class="fab fa-2x fa-facebook"></i>
   <i class="fab fa-2x fa-twitter"></i>
   <i class="fab fa-2x fa-instagram"></i>

Example 2: 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>