HTML

mat-tab-group change

 <mat-tab-group  [(selectedIndex)]="selectedTabIndex" (selectedTabChange)="onTabChanged($event);">
      <mat-tab formArrayName="staffMembers" #pft  *ngFor="let staffMember of formData.get('staffMembers').controls; let i = index">
        <div [formGroupName]="i">
          <ng-template mat-tab-label>
            {{staffMember.controls.staffMemberId.value}} <a>
          </a>
          </ng-template>
            <div class="form-group">
              <label for="name"> Name</label>
              <input type="text" class="form-control" id="name" formControlName="name">
           </div> 
        </div>
    </mat-tab>
 </mat-tab-group>