<ng-container matColumnDef="refundable">
<th mat-header-cell *matHeaderCellDef>
<p>Refundable</p>
</th>
<td mat-cell *matCellDef="let element">
{{ element.refundable }}
</td>
</ng-container>
refundable is a boolean value, and I want to show yes or no depending on whether it's true or false.