Post state to server on close Ionic cordova native IOS app

Post state to server on close Ionic cordova native IOS app
ios angular cordova ionic-framework ionic4
So, I have an app, which I has built with Ionic 4 and Angular 7. In my app I use NgRx/store and keep necessary data in state. And now, I want to save some state data on closing my app to keep it synced for other devices (for example there is the same user on IOS and on Browser).

For Browser and Android I use this event listener in my app.component.ts which works fine

@HostListener('window:blur', ['$event'])
onBlur(event: FocusEvent): void {
   if (this.userSignedIn) {
       this.storeService.sendStateToDB();
   }
} 

On IOS devices this event is caught, but post request isn’t executed. Only happens (with error) on next iteration on open app.

So is there any other way to implement it?

Also I thought about Observable timer to post state after some period of time, but it looks like costly operation. Thank you.

Irrelevant already. Solution had been found.