APP_INITIALIZER - TypeError: appInits is not a function

I would like to initialize some important values when my application starts (Angular v17).

app.config.ts:

export const appConfig: ApplicationConfig = {
providers: [
ConfigService,
...
{
provide: APP_INITIALIZER,
useFactory: (init: ConfigService) => init.load(),
multi: true,
deps: [ConfigService, HttpClient]
}
]
};


config.service.ts:

@Injectable({
providedIn: 'root',
})
export class ConfigService {
private http = inject(HttpClient);

private _config: any;
private _user: AppUser;

public getConfigUrl(key: string): string {
return this._config.urls[key];
}

public load(): Promise<any> {
return new Promise((resolve, reject) => {
this._user = new AppUser(); <-- normally a request to my node-express server
this._config = 'test';
resolve(true);
});
}
}


Then I got this error when I ran the application and did not understand why.

ERROR TypeError: appInits is not a function
at \_ApplicationInitStatus.runInitializers (core.mjs:31069:32)
at core.mjs:34973:28
at \_callAndReportToErrorHandler (core.mjs:31146:24)
at core.mjs:34971:20
at \_ZoneDelegate.invoke (zone.js:368:26)
at Object.onInvoke (core.mjs:14424:33)
at \_ZoneDelegate.invoke (zone.js:367:52)
at \_Zone.run (zone.js:130:43)
at \_NgZone.run (core.mjs:14275:28)
at internalCreateApplication (core.mjs:34948:23)

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