tweak

packages/svelte/src/internal/client/reactivity/async.js

@@ -17,12 +17,15 @@ import { async_derived, derived, derived_safe_equal } from './deriveds.js';
 export function flatten(sync, async, fn) {
 	const d = is_runes() ? derived : derived_safe_equal;
 
-	if (async.length > 0) {
+	if (async.length === 0) {
+		fn(sync.map(d));
+		return;
+	}
+
 	var batch = current_batch;
 	var parent = /** @type {Effect} */ (active_effect);
 
 	var restore = capture();
-
 	var boundary = get_pending_boundary();
 
 	Promise.all(async.map((expression) => async_derived(expression)))
@@ -45,7 +48,4 @@ export function flatten(sync, async, fn) {
 		.catch((error) => {
 			boundary.error(error);
 		});
-	} else {
-		fn(sync.map(d));
-	}
 }