in fact you know what, this whole thing is overkill. get rid of it

Author: Rich-Harris

packages/svelte/src/store/index.js

@@ -1,5 +1,5 @@
 /** @import { Readable, StartStopNotifier, Subscriber, Unsubscriber, Updater, Writable } from './public' */
-/** @import { Invalidator, Stores, StoresValues, SubscribeInvalidateTuple } from './private' */
+/** @import { Stores, SubscribeInvalidateTuple } from './private' */
 import { noop, run_all } from '../internal/shared/utils.js';
 import { safe_not_equal } from '../internal/client/reactivity/equality.js';
 import { subscribe_to_store } from './utils.js';
@@ -74,7 +74,7 @@ export function writable(value, start = noop) {
 
 	/**
 	 * @param {Subscriber<T>} run
-	 * @param {Invalidator} [invalidate]
+	 * @param {() => void} [invalidate]
 	 * @returns {Unsubscriber}
 	 */
 	function subscribe(run, invalidate = noop) {

packages/svelte/src/store/private.d.ts

@@ -1,10 +1,7 @@
 import { Readable, Subscriber } from './public.js';
 
-/** Cleanup logic callback. */
-type Invalidator = () => void;
-
 /** Pair of subscriber and invalidator. */
-type SubscribeInvalidateTuple<T> = [Subscriber<T>, Invalidator];
+type SubscribeInvalidateTuple<T> = [Subscriber<T>, () => void];
 
 /** One or more `Readable`s. */
 type Stores = Readable<any> | [Readable<any>, ...Array<Readable<any>>] | Array<Readable<any>>;
@@ -13,4 +10,4 @@ type Stores = Readable<any> | [Readable<any>, ...Array<Readable<any>>] | Array<R
 type StoresValues<T> =
 	T extends Readable<infer U> ? U : { [K in keyof T]: T[K] extends Readable<infer U> ? U : never };
 
-export { Invalidator, SubscribeInvalidateTuple, Stores, StoresValues };
+export { SubscribeInvalidateTuple, Stores, StoresValues };

packages/svelte/src/store/public.d.ts

@@ -1,5 +1,3 @@
-import type { Invalidator } from './private.js';
-
 /** Callback to inform of a value updates. */
 type Subscriber<T> = (value: T) => void;
 
@@ -30,7 +28,7 @@ interface Readable<T> {
 	 * @param run subscription callback
 	 * @param invalidate cleanup callback
 	 */
-	subscribe(this: void, run: Subscriber<T>, invalidate?: Invalidator): Unsubscriber;
+	subscribe(this: void, run: Subscriber<T>, invalidate?: () => void): Unsubscriber;
 }
 
 /** Writable interface for both updating and subscribing. */