On-item-sliding option icons

Hi All,

When I create an on-item-sliding, it has two options Message and Favourite. As you can see below. Message works perfectly, and displays the icon on the button. Favourite however does not display the icon. What list of icons are available for the options of an on-item-sliding?

Thank you

    <ion-item-sliding *ngFor="let result of employeeModels">
        <button primary>
          <ion-icon name="text"></ion-icon>
        <button secondary>
          <ion-icon name="ion-lightbulb"></ion-icon>

use class instead of name

        <button primary (click)="alert('todo')"><ion-icon name="text"></ion-icon>Message</button>
        <button secondary (click)="alert('todo')"><ion-icon class="ion-ios-heart"></ion-icon>Favourite</button>