vue dynamic way to add style

One,

<li v-for="(chatting,index) in item" :key="index" :class="{'user_right':chatting.user_id}">

User_id determine whether there chatting, if you have additional user_right class name

two,

<p :class="coms===1?'hear1':'hear'"></p>

Judge coms is equal to 1, if it is equal to the additional hear1 class name or class name appended hear