NgbProgressbar to show value in the bar

[zijianhuang]

Event though the manual says value is "Current value to be displayed in the progressbar...", it is not really displayed, as revealed in the ng-bootstrap source code as well at https://github.com/ng-bootstrap/ng-bootstrap/blob/master/src/progressbar/progressbar.ts. So now I have to use bootstrap bare metal like this:
<div class="progress"> <div class="progress-bar progress-bar-striped bg-info" role="progressbar" [style.width.%]="gap/14.4" [attr.aria-valuenow]="gap" aria-valuemin="0" aria-valuemax="1440">{{gap}} m</div> </div>

Please provide an option to display the value, which could be percentage or absolute value.