how to apply class conditionally in angular code example

Example 1: if condition in class angular 8

<i [class]="user.login_status == 1 ? 'fas fa-circle user_active' : 'fas fa-circle user_inactive'" aria-hidden="true"></i>

Example 2: conditionally assign a css class angular 9

<div [ngClass]="{'message': info.priority < 10,
                 'warn': info.priority > 10 && info.priority < 20, 
                 'error': info.priority > 30}">

{{info.text}}

</div>