tweak, types

Author: dummdidumm

packages/svelte/src/reactivity/create-subscriber.js

@@ -6,11 +6,11 @@ import { effect_tracking, render_effect } from '../internal/client/reactivity/ef
  * and calls the `stop` function returned from `start` when all reactive contexts it's called in
  * are destroyed. This is useful for creating a notifier that starts and stops when the
  * "subscriber" count goes from 0 to 1 and back to 0.
- * @param {() => () => void} start
+ * @param {() => (() => void) | void} start
  */
 export function createSubscriber(start) {
 	let subscribers = 0;
-	/** @type {() => void} */
+	/** @type {(() => void) | void} */
 	let stop;
 
 	return () => {
@@ -30,7 +30,8 @@ export function createSubscriber(start) {
 						subscribers -= 1;
 
 						if (subscribers === 0) {
-							stop();
+							stop?.();
+							stop = undefined;
 						}
 					});
 				};

packages/svelte/src/reactivity/index-client.js

@@ -4,3 +4,4 @@ export { SvelteMap } from './map.js';
 export { SvelteURL } from './url.js';
 export { SvelteURLSearchParams } from './url-search-params.js';
 export { MediaQuery } from './media-query.js';
+export { createSubscriber } from './create-subscriber.js';

packages/svelte/src/reactivity/index-server.js

@@ -18,6 +18,6 @@ export class MediaQuery {
 /**
  * @param {any} _
  */
-export function createStartStopNotifier(_) {
+export function createSubscriber(_) {
 	return () => {};
 }

packages/svelte/types/index.d.ts

@@ -1730,13 +1730,20 @@ declare module 'svelte/reactivity' {
 	 */
 	export class MediaQuery {
 		/**
-		 * @param query A media query string (don't forget the braces)
+		 * @param query A media query string
 		 * @param matches Fallback value for the server
 		 */
 		constructor(query: string, matches?: boolean | undefined);
 		get current(): boolean;
 		#private;
 	}
+	/**
+	 * Returns a function that, when invoked in a reactive context, calls the `start` function once,
+	 * and calls the `stop` function returned from `start` when all reactive contexts it's called in
+	 * are destroyed. This is useful for creating a notifier that starts and stops when the
+	 * "subscriber" count goes from 0 to 1 and back to 0.
+	 * */
+	export function createSubscriber(start: () => (() => void) | void): () => void;
 
 	export {};
 }