Fixed the types

Author: NullVoxPopuli

ember-primitives/src/service.ts

@@ -64,7 +64,10 @@ const promiseCache = new WeakMap<() => any, unknown>();
  * ```js
  * import { service } from 'ember-primitives/service';
  *
- * const loader = () => import('./foo/file/with/class.js');
+ * const loader = () => {
+ *   let module = await import('./foo/file/with/class.js');
+ *   return () => new module.MyState();
+ * }
  *
  * class Demo extends Component {
  *   state = createAsyncService(this, loader);
@@ -80,7 +83,7 @@ const promiseCache = new WeakMap<() => any, unknown>();
  */
 export function createAsyncService<Instance extends object>(
   context: object,
-  theClass: () => Promise<Newable<Instance>> | (() => Promise<() => Instance | Newable<Instance>>)
+  theClass: () => Promise<Newable<Instance> | (() => Instance)>
 ): ReturnType<typeof getPromiseState<unknown, Instance>> {
   let existing = promiseCache.get(theClass);
 

test-app/tests/service/create-async-service-test.gts

@@ -5,6 +5,8 @@ import { setupRenderingTest } from 'ember-qunit';
 
 import { createAsyncService } from 'ember-primitives/service';
 
+import type { Sample } from './sample.ts';
+
 module('createAsyncService', function (hooks) {
   setupRenderingTest(hooks);
 
@@ -100,7 +102,7 @@ module('createAsyncService', function (hooks) {
   });
 
   test('is singleton with await import and new', async function (assert) {
-    async function factory() {
+    async function factory(): Promise<() => Sample> {
       const module = await import('./sample.ts');
 
       return () => new module.Sample();