diff --git a/src/runtime/motion/tweened.ts b/src/runtime/motion/tweened.ts
index 4e9705fe96..83434cdff6 100644
--- a/src/runtime/motion/tweened.ts
+++ b/src/runtime/motion/tweened.ts
@@ -75,7 +75,7 @@ export function tweened<T>(value?: T, defaults: Options<T> = {}): Tweened<T> {
 	let task: Task;
 	let target_value = value;
 
-	function set(new_value: T, opts: Options<T> = {}) {
+	function set(new_value: T, opts?: Options<T>) {
 		if (value == null) {
 			store.set(value = new_value);
 			return Promise.resolve();
@@ -137,7 +137,7 @@ export function tweened<T>(value?: T, defaults: Options<T> = {}): Tweened<T> {
 
 	return {
 		set,
-		update: (fn, opts: Options<T> = {}) => set(fn(target_value, value), opts),
+		update: (fn, opts?: Options<T>) => set(fn(target_value, value), opts),
 		subscribe: store.subscribe
 	};
 }