is there any alternative for ng-disabled in angular2?

To set the disabled property to true or false use

<button [disabled]="!nextLibAvailable" (click)="showNext('library')" class=" btn btn-info btn-xs" title="Next Lib"> {{libraries.name}}">
    <i class="fa fa-chevron-right fa-fw"></i>
</button>

[attr.disabled]="valid == true ? true : null"

You have to use null to remove attr from html element.