diff --git a/packages/svelte/src/reactivity/map.js b/packages/svelte/src/reactivity/map.js
index e85836036d..2aca3eeabb 100644
--- a/packages/svelte/src/reactivity/map.js
+++ b/packages/svelte/src/reactivity/map.js
@@ -15,7 +15,7 @@ export class ReactiveMap extends Map {
 	#size = source(0);
 
 	/**
-	 * @param {Iterable<readonly [K, V]> | null | undefined} value
+	 * @param {Iterable<readonly [K, V]> | null | undefined} [value]
 	 */
 	constructor(value) {
 		super();
diff --git a/packages/svelte/src/reactivity/set.js b/packages/svelte/src/reactivity/set.js
index b601f4efb5..91e4b43bfe 100644
--- a/packages/svelte/src/reactivity/set.js
+++ b/packages/svelte/src/reactivity/set.js
@@ -26,7 +26,7 @@ export class ReactiveSet extends Set {
 	#size = source(0);
 
 	/**
-	 * @param {Iterable<T> | null | undefined} value
+	 * @param {Iterable<T> | null | undefined} [value]
 	 */
 	constructor(value) {
 		super();