How to Apply Conditional Logic on Varition.php?

If have added the custom code in my child theme.

now i want to apply condition

if (!empty(data.variation.note_field){echo "text exists"}else{do_something....}

	<table class="my_account_orders product_spec_tbl">
	<tbody>
	<tr>
	<th>Notes</th>
	<th>Size</th>
	</tr>
	<tr>
	<td><code>data.variation.note_field</code></td>
	<td><code>data.variation.size_field</code></td>
	</tr>
	</tbody>
	</table>