how to collapse with ngx-bootstrap angular without a flag
问题 i am trying to do a collapse animation, but without the boolean indicator isCollapsed , because i have a lot of elements and i don´t want to make a lot of booleans, there is a way to do that without a boolean indicator? <button type="button" class="btn btn-primary" (click)="isCollapsed = !isCollapsed" [attr.aria-expanded]="!isCollapsed" aria-controls="collapseBasic">Toggle collapse </button> <hr> <div id="collapseBasic" [collapse]="isCollapsed"> <div class="well well-lg card card-block card