mempool/frontend/src/app/components/miner/miner.component.html

<ng-template [ngIf]="loading" [ngIfElse]="done">
  <span class="skeleton-loader"></span>
</ng-template>

<ng-template #done>
  <ng-template [ngIf]="miner" [ngIfElse]="unknownMiner">
    <a placement="bottom" [ngbTooltip]="title" [href]="url" target="_blank" class="badge badge-primary">{{ miner }}</a>
  </ng-template>
  <ng-template #unknownMiner>
    <span class="badge badge-secondary">Unknown</span>
  </ng-template>
</ng-template>