угловой условной показ подсказки
<td mat-cell *matCellDef="let food" [matTooltip]="food.name" [matTooltipDisabled]="!(food.name.length > 10)">
Banana in Transit
<td mat-cell *matCellDef="let food" [matTooltip]="food.name" [matTooltipDisabled]="!(food.name.length > 10)">
<button [matTooltip]="1=1?'show this text':'else this text'">
conditional tool tip
</button>