refactor(on-before-delete): async

examples/svelte/src/routes/examples/overview/+page.svelte

@@ -177,9 +177,10 @@
 	}}
 	on:selectionclick={(event) => console.log('on selection click', event)}
 	on:selectioncontextmenu={(event) => console.log('on selection contextmenu', event)}
-	onbeforedelete={({ nodes, edges }) => {
+	onbeforedelete={async ({ nodes, edges }) => {
 		console.log('on before delete', nodes, edges);
-		return true;
+		const deleteElements = confirm('Are you sure you want to delete the selected elements?');
+		return deleteElements;
 	}}
 	autoPanOnConnect
 	autoPanOnNodeDrag